Thank you both for your insightful comments! I hadn't heard about anger being a secondary emotion. Yes, I was incredibly disappointed when I saw that he had signed up for all the holidays, especially since he was under the impression he was on the hook for just one.

Maybe I did mean to scold him. I'll have to be careful not to do that next time, as you are right that he has some childhood memories about being scolded for things that shouldn't have mattered.

But I had color coded the list! We had talked about it just before he left for his meeting. How could he forget? I still don't get it. He told me that he is just an absent-minded person and that's not going to change.

Maybe my problem or primary feeling here is that I can't stand this outcome but there's nothing else I can do to change it. He has said he will try to switch days with someone, but that's not likely. He got stuck with those dates because no one jumped in to volunteer, so he did, trying to be helpful.