I don't think I ever did something too embarrassing but on the topic of forgetting things on characters I always seem to forget minor details that aren't in my character sheet.
My protag has a bloodied dress and bandages on right arm and I forget these often, looking over the page after I finished and quickly scribbling it in after realizing it.
Oh, typing this now also reminds me of something I saw that I needed to fix, in one page I posted someone has two right feet, I need to go fix that now.