Our bread shop tried that one year. He baked laxatives into the bread, we got our own back though. You should have seen the baker loo after we'd done with it.
Some joker has rigged all the seats in my office with an unpleasant surprise for the owners. When someone sits in one they soon discover the arse-nail the swine left for them.
All the shops around here have there christmas stuff out. Before I moved I never saw a christmas tree up prior to December 12th. I wish I was still in my old street.