I just sat down and started speaking to an old man once just so my friends would think I was nice.
That sounds odd. Why did you need to pretend to be nice?
I hated my friends at the time because they were all so much nicer than I was.
It's a good thing that you took the time to talk to that old man but doing it just to impress your friends was kind of cruel and unfair to the old man. It's a good thing he didn't know why you were doing it because he likely would have been heartbroken.
It's no biggie. I did what I felt like doing at the time.
It would be better if you could learn to do these things to actually be nice to people, instead of just to make yourself appear nice. It really shouldn't be that much harder.