I am 4 years post-op RNY. As far as the inner me, I did not detect any change.
But some individuals do. I think perhaps it might be expectations. They might believe that if they lost the weight, everything in their lives would change for the better - that overweight was the root cause of all their personal problems. It doesn't.
In my case I had the surgery because my obesity was causing me to slide down the slippery slope of bad health conditions (high blood pressure, diabetes, sleep apnea, severe acid reflux [Gerd]). The surgery corrected those conditions and I am very please to be healthy again. I also was pleasantly surprised on how easy it was to drop the weight because after the operation I lost my hunger. And I was also surprised by the fact that I went from a size 3X in shirts down to a size Small and from a size 46 in pants down to a size 33. It meant that I could shop in department stores again and replace my wardrobe with the latest fashionable styles.
Perhaps another component is hormones. As you lose weight, the chemicals and hormones that were stored in your fat cells are released into your body. These will pass through your kidneys and be expelled in your urine. But they can generate a flush of hormones during the weight loss phase and in some people dramatically affect their mood. This hormone rush generally simmers down once you transition into maintenance. It is important to meet your daily fluid requirements, because it take fluids to flush these hormones from your system.
Another component to your question is how the outside world treats the obese you from the slim, fit you. People treat fat people differently. Some comments may rub you wrong. Sometimes this is out of jealousy. Some people perhaps may even wish you to fail because they are obese and do not want to follow your path.