I eschew social media for two reasons, in order of importance.
1) Admittedly, I don't trust my own impulses. I would be that person "that Tweet has since been deleted" too often.
2) The whole atmosphere. Facebook & Instagram--a cesspool of self esteem/ego/comparison-behavior/reactionary arguments, hurt feelings, regrets, & drama. It already destroyed a generation of young people, but frankly, I don't think it does many adults all that much good either, although we think we are better at insulating ourselves in our great maturity and thick skin.
Of course, some people swear by them. More power to them, I am just not one.