Horribly dominate the jukebox
Look, your love of Semisonic is yours to share. But when you toss $10 in the jukebox and play their Greatest Hits album straight through -- twice -- you're also basically doing the musical equivalent of Chinese water torture to your barman. Also, does Semisonic even have a Greatest Hits album?
Graze the garnish
The maraschino cherries, olives, oranges, and lemons are drink garnishes, not buffet items you should contaminate with your gross fingers.
Close a tab, then start a tab
Sure, maybe you changed your mind about that last drink and opened another tab. It was fine until the fourth closed tab of the night. Now you're just wasting paper, and racking up charges for the bar, and generally being as annoying as possible. You shouldn't have used all your cash to play "Closing Time" four times in row.