I think it depends a great deal as to what level you intend to take lifting. I would be hesitant to call casual lifting and healthy eating BBing. Be it just to get in shape, or look better then your friends, I would classify this as a lifestyle choice and hobby. To me it only becomes BBing when it stops being about getting in shape, looking better then person x, or having those ripped abs for summer, and becomes focused individually on yourself, and on BBing goals.
Now, most would assume this means you begin competing or intend to compete, but I do not believe this is always the case. I know many lifters who for all intents and purposes are large, ripped, BBrs, but do not compete. Most have once, found they hated it, and moved on. Competition in BBing is a strange thing. It's uniquely detached and removed from the actual day to day efforts of the life. You train and diet to develop the physique, but then the actual competition is a beauty pageant which has nothing to do with training. Thus one can love training and developing your body, but not be too found of painting yourself orange and flexing on a stage.
True BBing is not about looking better then anyone else and is not as self-centered and egotistical as most believe. Its about taking your body and literally morphing it into something else. It's the journey, the hours and hours spent under the bar, training, puking and passing out to get those last few reps, knowing it's what you need to do to reach your goal. The diet, the discipline, it's a form of meditation. SF79 said it very well: "When it is just me and the iron, nothing else matters in the world. It's my moment of zen even when I have to pull myself up from the leg press because my quads are too fried to support my weight."
To BBrs it's more then a hobby, it impacts and is every part of your life. What you eat, when you sleep, how you move, how you think. When your friends ask you out for the night the first thing you think about is how much food you need to bring, and how/where you can eat it. You bring a beach cooler to work to fit all the meals (and pack an extra just in case you get stuck, missing a meal is unthinkable). You miss social events to train, you eat things, not because they taste remotely good, but because they will help reach your goal.
Yes we're a little obsessed, but that's the sport and we love it. People jump off bridges, climb mountains, and do all number and manor of crazy things. But they do it because they love it, it's part of them and they wouldn't want it any other way.