Improved Quality of Life
With loss of weight comes increased energy, better self-esteem, and greater social acceptance.
Increased energy
Most patients do not experience the hunger they had prior to surgery, so they become less preoccupied with food. As they lose significant amounts of weight, patients find that they have more energy. The shortness of breath associated with everyday chores of housework or playing with children disappears.

Better self-esteem
With progressive weight loss, the person begins to feel proud of the new shape he/she is attaining. In fact, a person can actually be stylish since the department store clothes now fit. A person discovers outside interests as the focus on food diminishes. The feelings of self-consciousness and shame are gradually replaced by feelings of confidence and self-control. All this begins to happen even after a few months after surgery.
  Greater social acceptance
Because of the prejudice against the obese in society, losing weight increases social acceptance and opens doors for better work opportunities, friendships, and even intimate relationships. It is not infrequent for patients on welfare to become employed, or for singles to marry.

It is very important to remember, though, that weight-loss surgery is not a "magic wand" that will cure all problems. It is a tool to be used in conjunction with diet and exercise to achieve a healthier and fuller life.
Other benefits of surgery:

Improved health

Maintained weight-loss