I have a 3.3 year old and a 3.5 week old. The trick to not being too pissed off at a 3 year old is to remember that he is just fucking three years old. He isn't going to listen to everything you say. Most things you tell your kid are about long term socialization that he is certain to learn, so don't stress about it.
You don't stress about it, but you do enforce it. You need to get good at not caring about crying. Crying is the sound of weakness leaving their bodies :)
Having a kid is extremely satisfying. I can't imagine I'd be happier without mine. If you average out these opinions across most of society, the amount of information relevant to me approaches nil. So don't not have kids because of some statistic with happiness research.