Either they're trying to be nice, feel better about themselves or they want something out of you. Welcome to humanity.
how do you know they don't? maybe that's all they can offer and yet you are expecting more? Each people care differently.... try to see from their point of view and see what you are missing? Sometimes... people get disappointed because they have high expectations about what to receive and get from others.
If it's a guy, it's usually for sex.
Its a facade. I mean, most people hate their jobs which include helping people, being hospitable, etc....but still, they ACT like they care so they dont get fired. A lot of folk are just in it for the money. They could care less about you. Whenever someone or something deems true is usually when you can say, hey i'm really glad you care about me!
It's a norm of society.