Even when you think you can detach yourself from the characters, you don't. Because you're spending so much time trying to realize this person and make them real that they do infect you, in a way. And you do take them home and live with them, even if you think you're turning the character off. But in order to pull off a role convincingly, you wind up thinking about that person all the time, and it does sort of creep into you. And then there are things that you'll respond to, or react to in a very different way than you would normally.