Niceguy - at the most basic level you are right - weight gain results from excess calories ingested over energy expended. What people, myself included, have been trying to do on this thread is to explain why we do this. The reasons can be very complex and not easy to tackle.
For example - the issue about not wanting to go to the gym because you feel unattractive. I do not think that society is accepting of fat people, and I tend to think that I am being negatively judged wherever I go. I have catastrophically low self-esteem. Most gyms I have been to seem to be full of fit, attractive, slim people, and it is very easy to believe that they are going to judge me even more than people on the street (probably a false assumption, but I bet that I would see the 'Good God' reaction from you if you saw me exercising, and would be so devastated that I wouldn't see the 'good for her' that followed it). Put all that together and you may be able to understand that going to the gym is bloody difficult for me, and if I feel uncomfortable and stupid-looking in my exercise gear, that is going to make it worse.
If it truly was as simple as consume fewer calories and exercise more, and I had no underlying issues complicating things, I would have lost the weight years ago. As it is, I am concentrating on losing the depression, as that is the problem which is more likely to kill me - no exageration - I have gone through periods where I thought about suicide on a daily basis, and was only held back from it by the thought of the hurt to my family, but I know I would only have to go a bit further into the darkness for the pain of the depression, and the need to escape it, to outweigh any considerations for anyone else. I just haven't quite reached that tipping point yet.
So I am working on my mental health, aiming to achieve stability and peace, and an ability to enjoy life, because then I feel I will be in a far better place to look after my weight. As I said earlier in the thread, I don't even like myself at the moment, and it is hard to care for and look after something you don't like. Hopefully I will get to like myself, and that will help me concentrate on losing some weight.