Ask YC: team that you wanted to fund, but one member you didn't like?

A couple guys I collaborate with want me to join them on their YC application. I'd like to do it, but I'm old and I've already been rejected by YC twice in the past (once with written, once I made it to the in person interview). I'm worried that having me a part of their submission will lower their chances of getting in. I think they have a good chance otherwise.

Have you ever had a team that you wanted to fund, but ultimately decided against because of just one member of the team that you didn't like?