#1 is
mood improvement/sanity. Workout time is my ME time. Over the years, I've trained family & friends to understand how important it is to me.
#2 is
habit. I've worked out for so long now that it's a habit like brushing my teeth. My day feels incomplete if I don't exercise (except planned rest days, of course).
#3 is
health. I definitely tend to work the "calories out" side of the equation better than the "calories in" side, i.e. my workouts are better than my diet
(working on that though).
#4 is
appearance. Approaching 59, I find that appearance isn't as big a motivator as it used to be, but I don't want to be forced to buy bigger sizes either.
Interesting thread!