Some wag amongst them is guaranteed to say "Cheer up, it might never happen!".
To which you solemnly reply, "It already has." and you slowly and sadly walk away…
Definitely makes 'Wag' look like a complete prick!

Another good one needs a companion.
Wear something really outrageous (I wear a HUGE, sequined, velvet bow-tie) and wander around the city at lunchtime. When you spot someone in a group looking at you and then turning to her friends and obviously muttering "Don't look now, but…" that is your cue. In a voice designed to carry clearly to the whole group, tell your companion "Did you just see that woman? She's telling her friends not to look at me!" You may elaborate, but I can tell you that, having been caught out in a social faux pas your 'victim' won't know where to look!
