No room for Misconception.
Me: “Over 18”
Man: “Oh then I bet you’re gonna be out this weekend down at the pub partying”
Me: “No actually I have college work to do and seeing my Godparents”
Man: (laughs) “Yeah yeah, common your over 18, I bet you’ll be getting out on the town”
Me: No I already told you, I’m seeing my family and have college work to do”
Man: Yeah sure *winks*
I get this on an occasional basis, where people automatically assume something about me before even knowing me but because I am over 18 or British, they think I must be doing what the majority do too.