My problem with those social networks, in general is the fact that they became a freak show, where people have the need of living their lives accordingly to what other people want to see.
So, they like to achieve things in order to show other people and get more "likes", not because they really want to do something.
It creates a parallel reality, where people are "happy" and beautiful and successful and traveling with an eagerness to feel other people's acceptance and envy for what they achieve.
This is what I don't like, how people make everything so shallow and the need of sharing everything to be more "sociably" accepted.