Was at a conference type thing. Most people in the sector I work in are 50+. Someone asked a question about how we get more young people involved and the the person presenting was like, "well look, Smee's a young person and a lot of the people he works with are young people, Smee tell us how you lot got young people on board".
Not expecting to be put on the spot I panicked a bit and did some waffle about the various people I work with and them being young. Then she followed up with, "yeah but HOW did your group get them involved?" and after more waffle about demographics and luck I said something not quite as bad as but to the general effect of "the people who started our group recognised that as women in their 60s they weren't capable of doing this project so actively identified the people who were and recruited them".
Not only does this obviously make no sense, but is pretty offensive to older people and massively offensive to women - gender had been no part of the conversation before then so I effectively just outed myself as a massive sexist for no reason.
Not many people wanted to talk to me over lunch.