Complete 100% of the game.
Glitch: Coffeehouse Break-in
If you go back to Venice on Sly 3, you may notice the coffee house near the
police station is inacsessable. This is not true, if you know where to look.

Walk up to the front entrance of the police station(the vent on top has been
boarded up), and you will see an interaction symbol.

Hit the circle button to open the door. Instead of opening the door, the camera
will zoom across the plaza and open the coffeehouse door. When the room loads,
you will be in the coffeehouse! Not useless, and fun.