DD8 is like this, although usually without a tantrum. I have tried coaching her about respecting the interests/ideas of others - and she either doesn't "get it" or (very possibly) just doesn't WANT to get it. She is very much, "my way or the highway," generally. It is sad (to me, not her), but if another child starts to walk away after she asserts herself, she lets them, without a second thought. She'd just rather do it her own way, and she is actually incredibly self-entertaining. Not sure how to help her other than keep repeating my message, with the hope that some day she will listen.
Still, she is quite gregarious, and she seems attract people merely because of her enthusiasm. The problem starts when she goes into major "boss-mode." (sigh)
