I think that's what this guy is doing. He's young, he's confident (to a point), but he lacks the wisdom and ability to reflect that comes with age.All of the things you mention occurred to me by the time I was 19. There's a difference between young people who are sprinkling their brains with alkaloids[2] at raves and the young people that are sprinkling their brains with DHA, creatine, and glutamine.
I also realize that there's a delicate balance I have to reach with regard to confidence. It's not easy to reach this balance, because on the one hand, young people are treated like second-class citizens (in some circumstances), but on the other, you need to have a lot of balls to do a startup, to charge what you sholud be charging, and claim the work you do is as good as that of an older adult's. This is especially true because claiming you are equal is taken to mean arrogance, even though the evidence for the alleged inferiority of the young is lacking. In objective contests like chess, war, athletics, hacking, and mathematics, there are many very proficient people who are very young.[1] This is not the case in established corporations, politics, or the job market. Finally, people always want to feel superior to others, and while they can't express this desire for superiority by being racist or sexist, they can do so by discriminating based on age.
Sometimes behavior that is acceptable in a male 50-year-old CEO is considered unacceptable in a female of the same age or a young guy (there was a Harvard Business School study that showed something to this effect; it was a case study of a CEO that has to make certain decisions. The male was considered to be "tough but fair" or something, while the woman was considered a bitch. The case studies were identical but for the gender of the protagonist). So, would you say he's being arrogant if he were 50?
Now, is Sam being a douche? I don't know, but I do know not all young people are the same.
[1] Fidel Castro, Alexander the Great, Octavian, Bobby Fischer, Steve Jobs, Bill Gates, Woz, most athletes (for many reasons), Reimann, etc.
[2] NB: I'm not talking about caffeine or ritalin.
Edit: I didn't mean to get on your case, petercooper; you seemed to have said things in good faith. I guess you touched a nerve...