I'll open with three:
1. The coast to the bench. I know the rule about the exiting player needing to be three feet from the bench is not strictly applied, but still you're losing a second or two for the entering player. The optics are terrible. That said, it's an established and accepted way of leaving the ice.
2. Same issue — coasting on the backcheck. See Gilmour, Doug and one of the worst days of our hockey lives. Also well established and seemingly accepted.
3. This one will probably stroke me out some day if the Sabres ever get back into the playoffs — four seconds left in a period, the puck down below the Sabres' goal line, defenseman grabs the puck, unchallenged, and rings it up the boards onto the stick of an opposing player for a screaming shot at the Buffalo net.
Go ahead. Unburden yourself. You are amongst friends.