Obsession is kind of weird when you think about it. I mean really, is it a bad thing? It can be a good thing. I personally feel obsession is a healthy reaction to the human need to know everything about a subject. Or at least that makes it justifiable.
Take for example my hobbies. A person may learn to knit, but not immediately have 38 books on the subject. I, on the other hand do. A person may learn to spin, but not buy multiple spinning wheels and have a closet full of wool that would easily last through the end times (by the way, I recently pointed out to my sister that that is a survival tactic - if the world ended, I could trade clothing for food!), or maybe learn to weave on the first loom instead of buying 23 books (harder to find than knitting books) and 3 looms.
But I do all my hobbies this way. Many hobbies now dead and buried in the recesses of my memories, and the current ones. Take my aquariums. A lovely hobby, tranquil, peaceful, full of fun. I have 6 tanks. And multiple websites that I frequent where people talk about fish. But do you realize how peaceful it is to sit in a room with 4 fish tanks bubbling away. Of course other family members say it sounds like the ocean, I say good!
I wonder what the difference is in personality that makes some simply know how to spin, and others to be driven to know everything about it, and to conquer the hobby? Many people are simply content to hike a mountain trail, others climb Everest. Probably a good thing I've never taken up mountain climbing..