That's because there is no such person in this world that are "too good".<quoted text>
You are wrong, there have been people and there are people in this world that are too good. They honestly don't want anything, but it's a very hard state to reach, so people like that are very hard to find.
Humans use each other for their own gain all the time. They've done it in the past and they will in the future, until humans self-extinct because we used each other up to nothing.
These people may SAY they "honestly don't want anything" - but yes, they DO want something - the acknowledgment of the fact that they honestly don't want anything.
Don't let them fool you. It's phony.
It's STILL a "LOOK AT ME!"
If their good deed is not at least acknowledged, trust me, they'll eventually begin to feel used. And they're right - they HAVE been used.