Sometimes I'm somewhat "guilty" of kindness that asks for something in return, like I try to be kind because I know God will reward me or good karma will boomerang it back to me. But I like showing kindness, either unconditional or conditional, what matters to me most is how it affects the other person, if I made his/her day or uplifted him in a way then it serves its purpose.
I think we all do it on occasion and being conscious of it allows us to correct the behavior. Thanks for the great the comment!