Give yourself some credit here. Walking 3 miles is an accomplishment especially if you do it regularly. We evolved to walk, not to sit around all day. Simulate being the hunter gatherer ('modern' ones e.g. in Africa walk 3-8 miles a day), its good for your health to use your body for what its supposed to do. It's like driving the car every now and then so you don't get flat spots on the tires.