This video I feel summarizes addiction quite well.
If you were perfectly healthy and wealthy and just as lazy as hell you might be able to just hire someone to carry you around to every anywhere you wanted to go, do anything that needed to be done, lift anything that needed to be lifted. This would have serious effects on your body, you'd lose muscle mass and become weaker and weaker over time to the point where you'd not just want your helper to carry, do, and lift everything, you would need that help. If your helper left you'd either hire a new one or struggle to get up off your ass and recover from the mess you'd made of yourself. That's addiction for you.