Pop Culture is weird

Deviance is such a weird concept.
First of all, deviance is defined as departing from accepted social behavior.

Everybody is a deviant, there is no way that somebody could show no deviance whatsoever.
Not being a deviant would show deviance.

When I first learned about deviance, I instantly thought about two topics.
Boys normally have short hair, it has been that way for a long time now. But recently we have famous people like Justin Bieber and Harry Styles (who probably weren't the first people) who have changed that idea that boys should have short hair. Since their popularity, more men have been deciding to have a longer hairstyle, myself included.

The second topic that came to my mind is very popular among high school kids.
High school kids love the extravagant "promposal" where the boys ask the girls to prom in public places. I have done this myself. It started off as being cool to ask in front of a large group of people, and it has become very popular to do it.

So my  BIG question is... Is it considered deviance if it has become such a popular way of life in our society??