Good subject! I have always thought a lot about this. I used to really hate hitting the net more but the more experienced I get, it doesn't really matter to me. All misses are equally frustrating!
I will add, when I first started watching tennis matches as a young boy, and before I ever played the game, I got more mad when the players would hit the net. I was always like "Wow, at least get it over." After actually playing the game, I understand how it happens.