Now I see she probably actually believed my complaining was real and not just me venting to vent.
EXACTLY. I think that's precisely what happened to me too. The whole time I thought W felt the same way I did, that it was aggravating to have so little time to do anything else. So I thought I was complaining to a sympathetic ear. But she interpreted it as my true feelings about going rather than just venting. It's confusing to me because we always sat together at the events and I always mentioned to her how proud it made me feel to see our kids doing these things, and how wonderful their performances were/ are. So I would have thought that she understood the venting (which was usually done before we had to go somewhere, never at the actual event) was in fact just venting. Lesson learned!