One thing that nobody mentions about a startup is that if you choose co-founders, you should probably choose someone you've already had heated disagreements wit

One thing that nobody mentions about a startup is that if you choose co-founders, you should probably choose someone you've already had heated disagreements with - the more personal the better. In fact, if you started out hating each other and then ended up working together out of circumstance and found that it worked well on a professional level - that's probably the best scenario. You really need to be able to look each other in the eye and say "What the fuck are you talking about? You're full of shit." without feeling any emotion whatsoever other than perhaps a certain amount of healthy intellectual competition. There's plenty of uncharted territory that's going to be covered, but that shouldn't be one of them. Especially if when the heat and stress go high, one of you turns out to be a wimpy emotional pushover and the other one is a psychopathic aggression-monster.