What should I do if somebody tell me go away at nightclub or a bar for no reason?

If it's bouncers or one of staff at bar then yes has to listen because it's their property not mine.

I am talking about when you bumped into someone who just another customer who stop by bar.

Let say there is empty seat and you want to take a rest so you go there to sit on. Somebody next to this chair telling you go away.

Now should I listen or not listen? They are not the boss.

Or maybe you gonna suggest better listen anyway even if I legally don't have to. However I do need some place to sit soon or later and I do want to enjoy my drink and listen to music.