When you have the Choice!

One day I was between a very hard choice, between Me and Myself!! .. I guess that every one would reach some points where you have to make decision, which will not matter maybe for any one but yourself!! ... and maybe some other people.
The thing is, is doing THE RIGHT THING is always right? this is what was going on in my mind since days now! .. I know that I choose the right thing, but is it really right? because even if it is right, I don't really feel I want to do that! ... 
For example, if you are on a diet, and you really feel you want to sneak out with a chocolate bar, it will really feels good and this is what you want! ... but it is not the right thing! ... (this is a good example because every day I face it lol) ..
A lot of things are right but I'm not happy doing them, I don't know how should I force myself to accept what I choose alone! I can't blame any one on my choices! .. Did I say MY Choices? ... this is another thing, when I make decisions on my own! are they always right! ... I don't know? maybe not! .. and I'm suffering from my own thoughts *Smiles* ..
Seriously, should I skip the Gym? this is one of the things which are running back and forth in my mind, I'm too lazy! ... I'd rather to sleep and play Wii!!