In my case, it's because it really doesn't take that long to put together a simple meal, and living in a rural area far from good grocery stores & restaurants, I don't have many good eating-out choices anyway.
Maybe it's also because I learned to cook at an early age and I'm trying to encourage my sons' interest in cooking by showing them it's not this complicated, time-consuming task it's often made out to be.
I like good food. I raise chickens, the beef I eat is raised by a relative of a friend, I have a garden in summer, but I'm not a foodie. I like basic, peasant food.
But I think that above all, it's because I really just want a simple, relaxed life. Cooking the meals myself is both a means to that end and a way to keep my family happy and fed.
http://www.sampenrose.net/sprouts/
which I deliberately paralleled with Free Software:
http://www.sampenrose.net/tools/