Many of the large gyms in particular make it absurdly complex to cancel a membership, and count on people giving up and letting it ride. Though honestly I dislike most arrangements where you pay for a service whether you use it or not - imagine if your electric bill was always just $100, regardless of how much power you used... I am sure the gym owners will protest that if they only offered pay-per-visit it'd be more expensive, or they'd go out of business, etc.
Most gym membership are auto renewing fixed length contacts with hidden terms that are impossible to get out of early. Even if you want to cancel at the prescribed time they make you do things like come in in person to get the cancellation form and then you have to mail it certified mail rather than handing it to someone.
