If I decide to seek company of some people, because according to some metric M they are better than me, I am helping myself, because I am exposing myself to people better than me, but at the same time I am hurting them, because I expose them to a person that is worse than them, according to the same metric.
I am not convinced that being around people slightly worse than yourself is bad for you. Especially when you get into a mentor role. When you actively try to help others understand and improve, this forces you to think about what you are actually doing, which probably improves your behavior.
Disclaimer: purely anecdotal, and does not apply to all metrics.
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.