What did/do you feel dumb for finding something out way too late?

Since today, I never knew that the Avalanche logo had a puck coming down the bottom. Weird that I've never noticed that, and I've been watching hockey for at least 16 years.

It could be also that you didn't know a player got traded or played for a team. For example I was gone and I never had wifi when the Subban trade happened, and I found that out like two months later.

What about you?