When speakers at YC dinners take questions at the end, there's one I ask most of them: what do you know now that you didn't know when you were 24? The most common answer is to trust your instincts about people. If you're thinking of working with someone but something seems iffy about them, don't.

So you probably did the right thing.

Friends can help you screen people. Especially female friends, who often have a more sensitive social radar than men.