Have you ever been in a super crowded bar during happy hour and felt sorry for the cocktail waitress? There she is running around taking orders, pushing her way through the crowds, and carrying trays full of easily spillable mixed drinks. When she finally reaches your table holding a tray full of ten different martinis for your crew, it's a natural instinct to want to help the poor girl out (after-all she is in heels!) and grab a drink or two from the tray she has balanced in one hand. But wait STOP(!) you should never take anything from a waiter or waitress's tray. As much as you think you're doing her a favor, you're more likely to topple all of the drinks she is carrying. Holding a heavy tray full of various sized/weight drinks takes a perfect equilibrium that only the one handling the tray controls. If an outside interference unexpectedly screws it up, the waitress (or you!) could get soaked in beer or vodka. Let her do her job and hand you the drinks. If you really want to help her out, leave her a nice tip when you leave the bar.