Generally speaking, I'd say if your favorite actor knows *your* name then you might be bordering on over obsessive, or even creepy. Of course there are exceptions to this (I was a fan of this one show which had a lot of free promotional events - question/answer sessions and the like. I went to them. I also showed up at stage door of said show three times, once for my own autographs, twice because I was with friends who wanted autographs. One of the actresses did learn my name. I also had neon pink hair at the time though, which I think made me very noticable no matter what I did).
I don't think giving an actor a small gift at the stage door, for example a piece of fan art, is creepy. I think giving them expensive gifts, or giving them gifts more than once can be creepy.
~Yonah
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