In 1993, Nobel Prize-winning psychologist Daniel Kahneman performed a fascinating experiment to explore the veracity of the peak-end rule. Kahneman exposed two groups of people to ice cold water for varying periods of time. The first group was exposed to 60 seconds of 14-degree water. The second group was exposed to 60 seconds of 14-degree water followed by an additional 30 seconds of 15-degree water. That final 30 seconds of slightly warmer water made all the difference.

Although the second group was exposed to equally cold water for an even longer amount of time, they overwhelmingly rated the experience as less painful than the first group of people, simply because their exposure ended with a slightly warmer temperature. This experiment is often cited as a classic example, among many subsequent studies, supporting the peak-end rule.

Simply put, a person is most likely to remember an event or experience as positive or negative based on its ending. This insight has profound ramifications for understanding the connection between our experiences in the moment and our future memories of those experiences, which may not necessarily concur. What’s more, there may even be ways for us to positively influence our memories for the better. In fact, according to the peak-end rule, one of those ways is to consciously aim for a positive ending.

But why would anyone want to pay so much attention to the way they remember things before they’ve even experienced them? According to Dr. Susan Krauss Whitbourne: “There are many advantages to remembering the past in a positive way. In my research on personality and aging, I’ve found that the older adults with higher levels of self-esteem and wellbeing are the ones who tend to focus on the positive events from their lives. Long-term happiness often depends on your forming a favorable narrative of your life. Those who ruminate over their failures, disappointments, and mistakes are not only less happy in the moment, but also risk experiencing chronic depression.”1

Unsurprisingly, a similar sensitivity to the “power of the end” is found throughout Jewish thought and practice. A few examples, from among many, will suffice. For instance, the Talmud states that “a dream follows its interpretation.”2 Based on this teaching, our Sages crafted a ritual and script for one to recite in front of three witnesses following the occurrence of a bad dream. The person describes the dream and the witnesses then repeat in no uncertain terms that this was a good dream. By extending the arc of a dream into waking consciousness, this practice creates an opportunity for the dreamer to craft a positive ending to an unsettling dream. In other words, a dream does not simply end when the dreamer wakes up; the real end of a dream is arrived at in its interpretation. We thus give it a positive spin.

Another example is found in the Talmud3 in the context of how a person should ideally end a conversation. The Talmud states that we should be careful not to end an interaction while discussing frivolous or meaningless matters; rather, we should make sure to end conversations on topics related to spiritual or communal concerns.

Interestingly, as a source for this social sensitivity, the Talmud brings the example of the early prophets, “who would conclude their talks with words of praise and consolation.” Our social interactions with others often determine, or at least punctuate, our experience or memory of a given day. A single conversation can make or break our mood in the moment, as well as our feelings about life in general. Paying close attention to the way we end and imprint those exchanges can positively impact our lives and the lives of those we cross paths with as well.

One more relevant example appears in Rashi’s comment on the very last verse of the Book of Lamentations, one of the most profound meditations on existential exile and suffering.

The book itself, consistent with most of the rest of the text, ends on a dark and dismal note: For if You have utterly rejected us, You have [already] acted exceedingly harsh against us.4 In response to this despondent finale, Rashi refers to the custom of repeating the second-to-last line of Lamentations upon concluding the book: Return us to You, L‑rd, that we may be restored. Renew our days as of old.5

His comment reads: “Since he [the reader] concludes with words of reproof, he has to repeat the preceding verse again.”

We see in Rashi’s comment a clear expression of our Sages’ sensitivity to the power of endings. For had they not instituted the practice of repeating and thereby re-emphasizing a positive line from the previous verse, the community would be left in a state of disarray following such a deep reflection on the most painful chapters of its past, the destruction of the Holy Temples. In order to imbue the Jewish People with a more positive and hopeful message for the future, our Sages took the initiative to create a new ending that is focused on the eventual healing of all our wounds.

The Rebbe picked up on such ideas scattered throughout Torah and rabbinic literature and wove them together into a cohesive worldview and strategy for life based on the power of endings. This heightened sensitivity to the conclusion of things was one of many key ingredients in the Rebbe’s Positivity Bias. This expressed itself in numerous ways throughout the Rebbe’s life and teachings. One way in particular was the Rebbe’s preference for ending things—whether books, conversations, or farbrengens—on a positive and uplifting note. There are dozens of reported stories that attest to this particular practice of the Rebbe; here are but a few.

In 1973, R. Leibel Schapiro, along with a team of colleagues, had just finished the final edits on a Haggadah which contained the Rebbe’s commentary and insights. They sent a finished copy to the Rebbe for approval. The Rebbe wrote back to them and requested that they alter one small detail in the book—it did not end on a positive note. Indeed, the final words were in a footnote dealing with the mitzvah of circumcision: “…due to the pain of the child.” The Rebbe asked the editors to rearrange the text so that the book would conclude on an explicitly positive note.

The editors immediately wrote back that they would make the appropriate edits for the next printing, but it was too late to change anything for the many books already printed. The Rebbe replied that they should buy rubber stamps, have them engraved with the words l’shanah habaah biYerushalayim—next year in Jerusalem—and stamp each book by hand.6

We see in this story the Rebbe’s profound awareness of the impact of endings, as well as his commitment to doing anything in his power to ensure that every ending was portrayed in a positive light.

In a related incident, a visitor to the Rebbe’s library, home to hundreds of thousands of Jewish books, came upon a book that documented the sad and final chapter of Jewish history in a particular Polish region. To his amazement, after leafing through this rather obscure book, he noticed a few handwritten words on the book’s final page detailing the devastating end of that segment of Polish Jewry. The words read, “Umesaymim betov.” “We conclude with good.” The handwriting was the Rebbe’s. Again, we see the Rebbe’s consistent expression of this general principle of framing all endings in the positive, down to the smallest detail.7

It is also worth noting that the Rebbe’s sensitivity to positive endings was not only limited to books—it extended to other forms of media as well. When Joseph (Joe) Cayre and his brothers started their company, GoodTimes Home Video, and began producing children’s movies, Joe went to confer with the Rebbe about his new venture.

The Rebbe said to him: “A lot of children’s movies are violent—especially at the end—and they scare the children. Why don’t you make yours with a happy ending?”8 Mr. Cayre took the Rebbe’s advice and implemented it to great effect, positively influencing a generation of children who grew up on his company’s movies!

Significantly, the Rebbe’s practice of ending on a positive note expressed itself in interpersonal exchanges as well. When R. Chaim Citron was in high school, he and his parents had some disagreements as to his future direction. At a certain point when their conversation had stalled, they agreed it would be beneficial to ask the Rebbe for his input.

During a moment of charged silence that followed a lengthy and emotional discussion, the Rebbe turned to Chaim’s mother and said, “I want you to smile.” His request was so unexpected and disarming that she couldn’t help but do just that. Seeing her smiling from ear-to-ear, the Rebbe said, “Now that you’re smiling, you can go. I want people to be happy when they leave here.”9

This story says so many things, but in the context of our discussion, it is worth noting the Rebbe’s conscious decision to cap an almost certainly difficult conversation with kindness. We can learn from this that no matter how wide the gap between perspectives, it is always worth maintaining a sense of shared connection and goodwill for the benefit of all involved.

Another example is recorded in a series of letters10 between the Rebbe and bestselling author Herman Wouk, who was an Orthodox Jew. The exchange was initiated when Mr. Wouk wrote to the Rebbe requesting his opinion on a particular communal education project. The Rebbe, for various reasons, critically rebuffed it. But that is not where the Rebbe’s letter ended. Directly following his critique of Mr. Wouk’s proposal, the Rebbe proceeded to praise Mr. Wouk’s efforts in support of Jewish education, even referencing obscure clippings from Jewish newspapers related to his numerous projects.

Again, we see the Rebbe balancing a firm and unflinching stance on important and potentially contentious issues with an unwavering commitment to concluding every interpersonal exchange on a positive note. This story powerfully demonstrates the Rebbe’s ability to stand up for his principles without losing his respect for and connection to each individual.

Truly, the Rebbe did everything possible to make sure that everyone walked away from an encounter with him—whether it was in person or in writing—on better terms than they were before they met.

As a final example of this expression of the Rebbe’s Positivity Bias, it is touching to remember how the Rebbe would so often conclude farbrengens—when the Rebbe would gather with his Chasidim for a night of spirited teaching and prayerful song. Following hours of intense learning and reflection, as the farbrengen was coming to a close and the Rebbe was preparing to take his leave, he would frequently encourage the Chasidim to close the night by singing a joyous song whose lyrics, taken from Isaiah,11 are a perfect reflection of the theme of this chapter: You shall go out with joy, and go forth in peace. This song would accompany the Rebbe as he left the building and would continue to echo in the hearts of the Chasidim as they went home to their families and individual lives. In some small way, this song continues to echo for those who are open to hear it, reminding us all to end every experience and interaction on a positive note!