Oh boy - there's not enough room! My kids are almost 12 and almost 14 - I've had plenty of really bad moments that i'm not proud of! I'd say the one I'm most famous for is when I was furious with my husband and I threw a hard plastic cup at him from the kitch into the living room. It missed him and bounced off my DD's head (she was about 12 I think) - caused a small bump - this was about 10 minutes before a big soccer game she had. Uggggghhhhh. We were dealing with big stress at that time (FIL, MIL and my mom all in the hospital with serious stuff, sibling dynamics relating to the parents illnesses, etc.) Still no excuse!
Sounds like you & your firend have good attitude though - humor covers alot of errors. The biggest thing I needed to learn is to listen to my child, really hear what he/she has to say, acknowledge their feelings as valid, ask for forgiveness, own up to stupidity on my part for times I've hurt them and give lots of hugs.
I pray often that God's gracw will cover my screw-ups! Thankfully we have a big God.