So it's possible that actually all 100 people are assholes.
Only in the same sense that we can say "intenex wears a diaper" (because you were once a baby). Defining somebody by an off moment is one way to look at things, but I'm not sure it's particularly reasonable.
Depends on the type of moment... I like Lord Acton's exhortation to "judge talent at its best and character at its worst".[1]
I think that's good advice in general, but you'll miss the point if you stick too closely to it. You kind of have to weight your judgments. I mean, yes, a guy who beats his wife if he's had a bad day at work should be judged pretty harshly based on that. But if you-at-your-worst is somebody who is kind of grumpy and maybe a little bit selfish, you're a whole lot better than somebody who constantly acts like a crabby miser.
Even then, I know plenty of people who are never assholes, even in an off moment.