Regret is a painful emotion. And as you get older, it always seems there's more to feel regretful about. There are loads of memes about being in the shower and thinking about the comebacks you could have used against that annoying coworker, or perhaps your mortal enemy. But that kind of regret is nothing. I, personally, have been having a hard time thinking about all the hours I've spent nursing drinks at the dive bars where my friends work. I'd offer to help them close in exchange for cheap dr…