Never say "So what"
Look what comes out of not guarding one's eyes! The Gemara (in Sotah 47a) writes that while traveling with Rabbi Yehoshua ben Prachia, Jesus of Nazareth complained that the innkeeper's eyes weren't pretty. Rabbi Yehoshua pushed him away with both hands for his preoccupation with looking at women. Having been kicked out of the group of Torah students, Jesus went on to rebel against the sages and eventually established Christianity. So never say "So what!".