Most people understand that exercise is good for the body, mind, and spirit, yet very few Americans participate in a supervised exercise program with a personal trainer. Some of the blame for that can be attributed to the perception that personal trainers exist only to punish or exhaust their clients. The reality is that anybody, certified trainer or not, can make someone else sweaty, sore, and tired.
There are also a lot of people that masquerade as personal trainers.