A +1 sang at the reception, uninvited
I attended a wedding with my dad for a friend of his from high school. During the reception, this guy - who wasn't even invited; he was a +1 - goes up to the DJ and asks if he takes requests. The DJ affirms, and this guy asks for the microphone. The DJ obediently hands it over, which, in hindsight, I'm absolutely shocked about. This guy proceeds to sing a song (don't remember what) for the flabbergasted crowd for probably a good 2-3 minutes. And nobody steps in. The guy then happily hands the microphone back to the DJ and walks off on his merry way, with 0 awareness about what he just did. Total confidence that his actions were normal and unremarkable.
It was me. In my defense, I was 4.
Edit: clarity