I'm going to ignore a happy birthday message and continue to ignore an old friend
why are you going to ignore your friend?
I don't know, may be I'm planning to kick him out of my life.
Ignoring friends who are trying to wish you happy birthday is rude. They are not aware of why you are ignoring them so you should tell them instead of running away from the problem.
What I'm doing is good for me. I've warned him to stay away from me.
If you are ignoring them on purpose when they are trying to wish you Happy Birthday then doesn't that have a lot to do with them?