I think obsession varies by owner. Each person has a degree of obsession that bothers them to the point they do something. I think my tolerance is pretty low for obsessions.
Each of my dogs has something that they love more than anything else. I use these things for training and playtime. I keep the obsession level fairly low by having rules to each game. I might ask my dog to wait until released to get the frisbee or lie down before chasing the water hose. Sometimes mindless water/frisbee/ball chasing is allowed, but when I say "enough" its game over and I mean it. The frisbee goes up, the water is turned off, and if they don't calm down quickly, I go inside, or they can have crate time to cool down.
Not saying the dogs are perfect, there are things I would like to be able to do that I can't do yet. Like, call Rumor off of a frisbee in midflight after she has been released to chase it, but I can strive to work towards those things.