Right?
No everyone on here knows BroScience and according to that, if you workout for 15 minutes once every six weeks you will put on lbs of lean muscle, because not eating for 6 days and drinking nothing but Clam juice, followed by 4 days of Pop Tart Fasting will grow so much muscle you wouldn't even know what to do with it. Or its water weight, I don't know.
If you're tracking properly and on an honest calorie deficit, then most weight "gain" will be water or other "stuff", but will very rarely, if ever, be actual fat gain. That's the key difference when discussing this, is it weight gain or fat gain. Weight gain is fine, fat gain is not. It's not about what the scale says regarding weight, it's what your body fat % is, that's more important than seeing the scale go up or down. Losing weight, yes, you earned it...and you "earn" fat gain as well if you continue to eat at surplus.
Classic self-serving bias! http://www.psychologytoday.com/blog/in-practice/201301/the-self-serving-bias-definition-research-and-antidotes