Thanks to Facebook, whenever I go to a really great restaurant, I never tip the server. Instead, I write "Bob likes this" on the wall, flash them a thumbs up and walk out.
When I wasn't looking someone grabbed my shopping cart on Amazon and replaced it with one with a squeaky wheel. Of course my stuff was gone, and this one was filled with a bunch of "Preperation H" and a couple of those blow up rubber dounuts.