A personal trainer also gives you an excuse to take some time and invest it in your body. Self-motivation is very hard, even for the experts. Most personal trainers have a love of working out that, frankly, differentiates them a bit from their clients. The way they can help you get in shape is not by screaming in your face like a drill sergeant, but by inspiring you to enjoy getting fit as much as they do. Their expertise ensures that you do it right and that you don't overdo it too fast, either.