I won't pay for the sandwich I just ate.
What would you do if the owner followed you out of the sub shop?
I would punch him and make a run for it.
If you are starving with no money I can see that is a good reason to try to get away with it. However, you will be identified in a lineup and therefore be in big trouble after getting caught. Pay for it with money next time to avoid this kind of trouble.
I'm hungry and I don't want to pay.
If you get caught you will have to pay it back and you will be arrested. You need to pay for things you use. Like I said before if you are broke you can ask the manager and explain your situation, they might be willing to help.