Tony Robbins says we have 4 basic needs, and that all behavior is a result of attempting to fulfill one or more of those needs.
He says meeting just one need is enough to motivate us, but if a behavior fulfills 3 or more needs it will become addictive. So, just for fun, let's take a look at which needs I fulfill in the gym.
All four. Addicted? I guess so. It's interesting, right? Try looking at something you do frequently, and see if you can identify the needs that behavior fulfills.