I remember doing a dungeon with a tank who, a short way in, politely asked me if I could please switch to Emerald Carbuncle as Topaz was competing with him for aggro. I said, oh really, I didn't know that. I'll switch now.
No need to get butthurt about being asked to fix a problem. They just explained what the problem was and I took their advice to fix it. I don't get why people get shitty about stuff like that.