I'm a bit of an introvert and although I do really enjoy others company, it does drain me.
After work or meeting up with a friend, or bumping into someone I've not seen for a long time, I reply conversations, but the worst thing is that I worry that I might have thought out loud.
So just say for example I'd noticed something that you wouldn't say to them. Could be anything such as noticing someone's hair was messy that day, or their clothes weren't flattering, a passing thought that you'd never say out loud. I keep replaying conversations thinking that I hope that I did not say that out loud.