Likely, that's the very foundation of hypocrisy. Things are okay when it's us, or our closest ones, who do them. But when others do the same things (specially, others we don't like), it's like if life has suddenly lost its charm and we start singing the "it's all about me, you ruined my fun" song.
I confess, I enjoy when someone tries to rationalize this behaviour. For example, when following a trend. It's entertaining to read the list of reasons why they are right in following a trend, continuing with the list of reasons that attempts to portray as stupid sheep others that are following the same trend. It's a plus when they explain, how the fact that others following the same trend has completely ruined their experience. Mini point if they add, or imply, "and they sure have done it on purpose."
Just have fun. Perhaps you don't know it, but the world doesn't turn around your navel. Others may like having fun the same way you do, and that has absolutely nothing to do with you. Others may not even know about you when they're having fun the same way you do. Call them sheep if you wish, but remember: it's not about you.