Be Nice?

I have been growing up with this thoughts people been telling me to live by:
"Don't do something nice unless the person is nice."
I never agree with that, tho. If we do nice things to people based on that thoughts, wouldn't that be insincere? Are we waiting to be treated nice before doing something nice? Aren't we should be giving before taking?

This scene is captured from The Grand Budapest Hotel, one of my favorite artsy movie. Plain paper, sketched with pen and colored with pastel.

These days I found the thought seems appropriate.

I realized that I am not a very nice person. I rarely trying too hard to be nice. I only nice to people I consider nice. I think, even if one million people told me someone is bad but he/she's nice to me, then I will consider him/her as nice. So when I do good deeds to a particular person and he doesn't appreciate it (although I always consider him/her as nice), I feel ditched. Why did they do that? Even something interesting I mentioned in my previous post became lame because of it. Hmm.. I guess I need to see a psychiatrist (or pray harder - I am in the state called "futur" perhaps) for having too much negativity in my head.