Well, I went to my very first birth recently. Up until a few days ago, I'd never so much as been around a woman in labor (except for when I was inside one, as the baby).
I'm still processing it, but I'll say one thing: I wish it had occurred to me to look up some YouTube videos of transition, and not just "Jason's peaceful waterbirth!" Because, whoa, I was not prepared for that. (I know that women often freak out during transition, but I clearly did not realize what level of panic was possible. I also didn't have enough experience to be confident that it was transition, and if it wasn't even transition yet, yikes...)
P.S. I was an apprentice doula, mostly just being an assistant to a very experienced doula and observing.