What I think is, it doesn't hurt to be nice to someone. But dada, what I don't like is that a lot of people around us takes "being nice" to be going above and beyond and do something that creates unnecessary burden on the person doing it.
Yes sure, it doesn't cost anything to show kindness. But a balance needs to be reached. I don't see the point why someone should exhaust themselves trying to show "too much" kindness (if that's even a thing).
I will just behave whatever way I please at that point in time. I was a complete random disaster. As I grow older, I learned that doesn't work. So I tried slowly to become nice to people, and yes, there is a certain amount of acting involved.
Dada, two things here. I don't see it to be wrong if you are acting the way you want as long as you maintained the respect for people around you. For example, I like listening to heavy metal music on full volume. And doing that is going to cause disturbance to people in the house and neighbors. And if I go on and play the music anyways, then yes that is wrong.
This brings me to the second point, in this specific scenario, being nice would be to put my headphones on listen to whatever music I want. This is showing compassion to people around us and this should be the definition of being nice. This is Making the "correct" judgement call.
We could go on with such examples and I'm sure you will have much better examples than I can come up with, but what I'm trying to say is dada, we gotta find the balance.
Not playing nice doesn't mean we have to be a douche ;) We can still be a nice guy without playing the nice guy role!