The things I think you come out on top are:
Having a dog.
The love and companionship of a dog is the best. You have to take care of them, but I even like doing that. Also, they grow old and die, which is a horrible thing to go through, but I still think it's a no brainer that they're worth it.

Working out.
It only takes a few hours a week or so and you feel better, look better, and stay spry and healthy. I know some people despise working out, but I like it, so it isn't hard for me to do.

Eating healthy food and not over eating.
You feel better and look better, same as working out. If you usually eat healthy foods at normal amounts most of the time, I think it's definitely worth it.

These are all things that, for me at least, are easily worth what it takes to do them.

Anyone have anything else?