I've gone from BMI 43 to BMI 24.
During the process of losing weight it's amazing to get constant (literally constant) compliments. Great boost.
Once everyone I knew was used to my new weight I noticed how strangers treat me differently (in a better way). People are, genuinely, kinder and more willing to help or be nice to me as a slim person. They seem to want to help more, engage more. I feel much less invisible at a normal weight.
Something else tho, and it's this from PP:
Fat or not, I don't give shit
When I was fat, knew I was fat and had no intention to lose weight - I had a "this is me, I don't give a shit what you think" attitude. That has disappeared as a lost weight. I now do care what others think of me. Not just the physical size of me, but me as a person.
The "I don't care what you think" when i was fat was like a coat of armour. As well as not caring what others thought about my size, I extended this to not caring what others thought about my actions, behaviour, or just me as a person.
Upon slimming I lost this "I don't care what you think" attitude and found I did care if I was liked or judged to be a good person. I don't know why, there's probably some significant psychology at play but it's definately noticeable in me.