1) The last time you gave him a present he tried to give you one in return, if you know what I mean.

2) You'd have to borrow money from him to buy a card anyway.

3) The concussion from that time you saved his life works in mysterious ways.

4) Isn't he a Jehovah's Witness or something?

5) At his age you thought it best to not remind him.

6) You were too busy sleeping with his girlfriend.

7) Lame bastard needs to remind you of these things. It's not your fault if he's too lazy to give you good warning.