I cook at home most of the time for the following reasons:
1) Eating out is damned expensive. Especially now that we have a 12% tax on restaurant meals.
2) Figuring out the tip is always stressful.
3) Cooking my own meals means I can control what to put in my food. Sometimes I want more meat, sometimes more vegetables, sometimes I don't want so much salt, sometimes I want more spice. Those are hard to control when you eat out.
4) There is a sense of satisfaction when a recipe comes together to make something yummy.
Since I'm living alone, on a budget, and lazy, what I cook most are stews and soups. For a fast meal I'll do a variation of olive oil + garlic + tomatoes/other vegetables/sausage tossed with pasta (and good parmesan). Now that I'm not working I may start wrapping my own gyozas/dumplings as well (an afternoon of hard work but the payoff is immense---make a hundred or so, stick in the freezer, many meals of joy and happiness).
I really need a clean, comfortable kitchen to enjoy cooking, though. I don't do well with communal kitchens in dormitories or hostels. They just gross me out.
The downside to cooking is the washing up.
"Whatever you do, don't fall off the bridge! It'll be a pain to try to get back up again." - Private, DW 8