Why do we bet?

I sometimes forget how important this concept is, "Most of the time we bet only to get a better hand to fold or a lesser hand to call." When playing post flop, we have to resist our initial urges to bet every flop no matter what. There are reasons to bet, and they become more and more complex as the board progresses. Even if you are a religious c-better, you sill need to evaluate the cause-and-effect of a turn bet.

If I am betting and I am not either
a) applying pressure to a better hand or draw to fold
or
b) building a pot with a better hand

I am VP$P-ing in order to give chips to my opponent. He is causing me to make an unforced error, instead of me exploiting his mistakes.

another note is that sometimes a check accomplishes b, but on the next street. Knowing how and when to do this is a skill I have not yet cultivated, but I am now actively looking at to improve.