In my experience it was a mixture of boost in ego and energy. I felt so energized and good solely because of the fact that I knew I got the surgery done. 4 days post OP and I was walking around 4 miles without any of my previous ankle pain. Working out was always hell for me because my joints would HURT and I'd get so dizzy. When I started doing more (3 weeks probably) I was able to work out at ease and felt normal about it I didn't feel like I was going to have a heart attack after only a few minutes. I'm 20 so my experiences could be because of my age and current weight around that time (290-270) but working out will get easier quicker than you think.