I think you're OLD enough to answer this question YOURSELF
stop doing things for him/her
Just ignore and pass on .
If you did it for praise then you did it for the wrong reasons. When someone genuinely does something from the heart it shouldn't matter if that person appreciates it or not, the act of kindness is done for kindness sake and no other.
What makes you think they don't? Is it something they asked you to do?
well it means she/he is not good enough for you and they will lose someone who cared so much about them. it's their lose, not yours. cheer up :)