Eavesresponding
You peek into a conversation you're not supposed to be in, don't know what's going on, but you still think you need to add your opinion like it's the most important thing ever. It's like you think everyone else is dumb and you're the only one who knows what's going on.
'I didn't even get invited but I'm gonna talk.'
'You're all wrong, I'm right.'
'I'm not part of this but I'm gonna ruin it.'