It depends. The comparison I always make is to Gordon Ramsay, the (in)famous chef of Kitchen Nightmares fame. He's famous for two things: swearing constantly at

It depends. The comparison I always make is to Gordon Ramsay, the (in)famous chef of Kitchen Nightmares fame. He's famous for two things: swearing constantly at the subjects of the day's episode, and being entirely right--his strongest language comes out when someone has just done something absolutely indefensible. The balancing act here is that Ramsay's reaction is only okay because he's reacting to something that is obviously wrong, and that's what Linus does--he only starts yelling if you break userspace or the kernel. The advantage is that you don't have to, for lack of a better word, play footsies with the problem: "This is wrong, you fucked up, go fix it" is immediately clear, whereas an entire email consisting of variations on "I think you might have maybe done something wrong" is technically more 'acceptable' but doesn't get the point across. TL;DR: It's okay to yell at someone if they're being stupid, but you need to be sure.