Ok, just for the record, I'm an ADDer, but my best friend has ADD, too, (and she's not medicated :P) so I can definitely see both parts of the issue, if only in a limited sense.
One of the things my best friend does that gets on my nerves a lot is forget to call me when she says she will. I'm very good about that myself, so it annoys me to no royal end. But, we have been friends for 12-13 years, so I have basically just learned to not let it bother me. It's not personal, she does that with everybody!
There are other things, too, but that's been my main strategy, to realize that it's not personal and has nothing to do with how much she cares about me. She's always there for me when I really need it... like this past Saturday when I was feeling rather depressed.
Hope that helps.