Lately I've become more and more irritated by some players tendency to complain about dice and bad luck in their games, and in general try to explain their results by talking about bad luck or good luck, when dice modifications, or lack of such, has a lot to do with it. I can be both against me or someone else, but when some people talk about their games, they make it sound like the only thing deciding the outcome of a game is luck.
My question is how do you deal with it in a friendly manner? If I loose, I (for the most part) have no problems saying against it: it wasn't bad luck, but some gameplay mistakes, but it's harder to tell someone who just lost that it was their own fault. I you don't want to just say "fly better"/"git gud" and show them the middle finger, what do you guys usually say?