Why do some people allow themselves to become obese?

Sometime, I wonder why some people allow themselves to become obese. They don't even do execrise for years. One thing they don't realize is obesity can take their freedom of motion away. Becoming fat may be easy, yet it is still dangerous. I have little fat in my belly because I'm not good at a workout due to the lack of stamina. I could do a light exercise for a minute or few. If a person is lazy, someone should have encouraged him to do some exercises for his own health. Or be a workout buddy. They should not eat greasy foods all the time. A healthy fruit and vegetable should do a job.