First let me make it perfectly clear that I’m not certain how much of this is really about the human named Viggo Mortensen. Rather it is about a popular fantasy of who he might be, the figment of a collective imagination. I am guessing that many aspects of the fantasy and the real person overlap, but as I do not personally know Viggo, I won’t try to speak to that.
On the other hand, I’m afraid that I can speak to the potential for obsession. Perhaps I am fooling myself to say that I’ve experienced only a brush with these feelings, but at least part of me has been aware and chuckling with amazement and a wee bit of embarrassment since its onset in late March of 2004.