Guys, Why my male friend does not appreciate what I do for him?

Hi,
I have a male friend who I like and he was attracted to me (as he once said) so we decided to date. Before Christmas he broke up to travel with his friends (including a girl that he has crush on). Then he came back with apologies and let's start over but I wasn't the same so I said I don't like to have sex with him.
We eventually decided it doesn't work so let's stay friends. I like him as a friend. And he is lives alone without any family. So I invited his friends for a surprise birthday party and he did not even say a thank you. In the party I could say he likes it and he kept saying how surprise it is but never said later, Thank you for organising this.
I do these things because I like to do it. But still hearing a thank you feels good.
Help me if you can see it from his perspective please.
Guys, Why my male friend does not appreciate what I do for him?
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