For someone else? I'd probably do something like tamske, except go really extravagant and such, be wearing like a rented french maid outfit if I could afford it, and hope they pass out from absolute confusion, praying they don't actually go along with it.
I'd have suggested the cat ears and tail route instead of the french maid one, but I think everyone knows I'd refuse to take them off after.
As for my personal worst? It's never happened, since I'm usually pretty vocal on the matter, but if someone got me a gold and diamond ring, I'd be seriously pissed :O
I don't like gold, and diamonds are boring. If yeu got me something like that it'd mean yeu'd ignored everything I'd ever told yeu, had no clue whot I liked, and were just throwing money at me, so I'd be very GRRRR at them.
Titanium and cat's eye, all the way <3