Maybe this person has a bad memory?

I have been guilty of the same thing. Telling someone I would do or give them something and I honestly and truly forget about it. I feel horrible when it happens as I don't mean to be forgetful. I do appreciate it though if someone gently reminds me and I will do my best to follow through with it.

Sometimes life is so busy we tend to forget. And sometimes we have physical/medical issues that interfere with our memories. I think it's always good to try to keep an open mind about such things.