I checked Health, Money, and Other.
Health: This one is pretty obvious and I think it is the most important.
Money: I think that with adequate money, one can relocate (if desired), or engage in activities (if desired). I don't think you necessarily need a lot of money, but you might if you have a burning desire to travel constantly or take flying lessons, for example. Most of us probably don't really need to engage in expensive activities to be happy after a lifetime of LBYM, but only you know how much you will want to spend. A good retirement should mean that you aren't worrying about how to pay the electric bill, though.
Other:
(1) I think it is pretty important to know yourself and know what you want to do with the rest of your time on earth. Maybe I should have checked "spiritual life" to cover that aspect.
(2) I think it is also important not to be overburdened with responsibilities - - if you have to spend more of your time than you might like in caring for animals or kids, or maintaining a huge money pit of a home, I would think it might be hard to get the maximum enjoyment out of retirement.