Let's not forget 4. The Environment: Eating food that was grown just next to the place where you consume it reduces your carbon footprint big time. Further, growing organic garden provides habitat for more insects, birds and even small rodents than you can imagine. And last but not least it gives you the opportunity to make and use your own compost which is very beneficial for health of the soil and natural circling of nitrogen, carbon and other elements.
Growing your food gives you an intimate connection with the Earth that reflects on every aspect of your existence on this planet. You cannot overestimate its importance.