Okay.. yes, when your nice to others, Allah is happy with you. But forced-niceness (being fake basically) isn't very nice and at times can be kinda obvious (in which case, you'll just annoy people). Plus, Allah swt knows your intentions anyway.. so why the need to be fake to make Allah happy? Allah swt doesn't NEED our niceness, if we're nice we'll get rewarded for it by Him, we'll feel good & others will feel good aswell.. basically, it'll do US good. So we should try and be nice to people, and mean it.
Oh but if you don't feel like being nice to someone, just make sure you don't be nasty either :@:
Allah swt doesn't NEED our niceness.....hmmm
then why even be nice for once? what is a point if you want to seek ALLAH SWT's happiness?