Oh, bartenders. They do so much work to keep our nights out as fun and delicious as possible, and how do we repay them? Sure, most of us tip (hopefully), but sometimes, we do more harm than good.Have you ever seen how dirty and disgusting a bar gets at the end of a busy night? Chances are you don't always realize at the time, what with lights being so low and your alcohol intake blurring these finer details. Let's face it: When you're going out for the night, you're more focused on getting your drink, making sure your friends aren't fighting or crying, and finding some scrumptious pizza afterwards. Amidst these more pressing matters, it's easy to ignore everything that the bartenders are very soberly (sometimes) putting up with.Bartenders were asked to share the biggest things customers do that piss them off, and their responses might just have you watching yourself a little more closely next time you go to the bar!