Some shops over here have their security shutters on the inside of the glass (If the shopfront is listed as of historical significance for instance) the only problem is that when you're drunk and a little bleary eyed you can't see this fantastically clean glass and wander up to look at something interesting through the shutters only to come to a painful stop six inches or so away from where you expected.

The Early hours of Saturday morning are always best for observing cases of mystical forcefield collisions