So, the mood swing thing was something I didn't identify with ADHD until I saw it mentioned in a book called "Driven to Distraction". I can't remember the exact details, but I think in the first few pages the author talks about a patient who was often getting in arguments with his boss or spouse and losing his temper in frustration, and I guess what I took from it was that a lot of his emotional instability was either a symptom of ADHD or stemming from his inability to focus.

In regards to your comment about shortened temper on stimulants, I think this is very normal and expected, and I have experienced the same at times. I don't know how to explain it, but I think overall I'm more agreeable than I was before I was medicated. This might be an age thing; I honestly don't know. Maybe I just grew out of it (I was the kid who threw tantrums lol).