“Many did like R. Shimon bar Yochai, but they were not successful.” (Berachot 35b)

This means that they wanted to subject themselves to many self-mortifications in order to attain the level of R. Shimon bar Yochai. That is why they did not succeed. 1

When serving God, have in mind nothing but to bring gratification to the Creator, blessed be He, and not the attainment of [high] levels. 2