Manolo for the Big Girl had a lovely post about the phenomenon of
"I Carried a Watermelon." Those of you who did not grow up in households where a mother or aunt or sibling (or YOU) would watch a cantankerous VHS tape of Dirty Dancing at least once a month should know that when Baby, our heroine, first meets hunka-hunka-dancin'-man Patrick Swayze, the only thing she can think to say is "I carried a watermelon." And then proceeds to mentally beat herself up for not thinking of something, ANYTHING, better than that.
This isn't a case of foot-in-mouth. More like brain-has-no-response. Foot-in-mouth would have been as follows from a few years ago:
Tiny Emo Dude at Concert: Hey.
Me: Hey.
TED: You've got a beer.
Me: ...Yeah.
TED: How'd you score a wristband?
Me: I'm 25.
TED: WOW. You're OLD.
Me: *eyebrow* Thanks.
TED: *wide-eyed panic of Wants to Die*
Whereas a watermelon moment would be like this from around the same time:
Incredibly Attractive Barista: *takes my order, hands me coffee* Is there anything else?
Me: I like coffee.
IAB: *blank look* ...Good?
Me: *dies a little inside*
Have I got my distinctions down? Got examples of your own?