I may not even have Asperger's (that's why Im here, lol) but I do have OCD and I find that if I'm in a bad mood, I assume my boyfriend is in a bad mood too, and it can be problematic for us because I'll keep asking him if he's OK, again and again, and he starts to get mad. Self fulfilling prophecy. I am capable of empathy though, so I may be a bad example--but it's not as easy for me as it is for a lot of other people.
I also have a hard time when I'm in a great mood, and a friend calls me with problems, or if she's upset. Sometimes, I even get mad! But again, not sure if that's relevant....