OK here's one that has me grinning from ear to ear, but is potentially damaging for my friend. On iChat, you can add your own photos for the custom backgrounds in Video Effects.
In an amusing but childish video chat recently, he put up a background that might be considered offensive in some circles. OK, it was pretty offensive to anyone.
The problem is that there appears to be no way to delete the background, which could be a problem down the line if tech support, wife or colleague stumbles across it at some point in the future.
Anyone got any ideas?