I think one of my favorite DnD Things is when random rolls become retroactive Lore/Quirks for the character. Not even as a DM ruling, I mean something the whole table adopts organically, whether seriously or as a running joke.
- A paladin I DMd for failing every single perception roll turned into him canonically needing glasses and not realizing it.
- A combination of failed perception checks and concentration saves becoming a character having ADHD and that getting worked into the acting.
- My gnome barbarian with low intimidation rolls despite doing/saying some actually terrifying things suddenly having a voice that cracks like the "WHEN WILL YOU LEARN?! WHEN WILL YOU LEARN?! THAT YOUR ACTIONS!! HAVE CONSEQUENCES!!" kid when he shouts.
- Or my favorite, my tabaxi artificer, Gus, comedically failing every religion check when it comes to praying so now it's a whole plot point that gods literally do not perceive him.
(Yes this is an invitation to reply or tell me in the tags if you've had any canon-altering rolls like this I love PC stories)
In like the first or second session, my character rolled nat 1 perception despite that being her top skill, so I just decided that she's a useless gay who got distracted by the Pretty Woman the party just met. I also messed up her max hit points for the longest time so we decided that she's really just lactose intolerant and her daily milk coffee was ruining her