Earlier quoted context omitted.
Hahah right except that in this case the reward is purely intrinsic for returning to pay, while leaving without anyone knowing results in an extrinsic reward ($). "Being rewarded" is generally considered extrinsic otherwise you could just not do some bad thing and claim the feeling of knowing you didn't do the bad thing is a great reward in itself.
Dunno why you are so determined to say that my good deed (not stealing) was not rewarded. Cashier explicitly stated “honesty should be rewarded” and knocked three or four bucks off the price. Those extra dollar bills in my wallet are very much extrinsic. Why are you being so damn weird about it?
The parent you were responding to stated that people are not really rewarded for good behaviour after childhood. I'm not saying your deed was not a good one. I am saying that you are monetarily worse off for having gone back to pay and that feeling of having done the right thing, or the discount off the original price is hardly an example of good behaviour being rewarded, especially when you compare the reward for not doing the right thing. If there is only right and wrong and the reward for doing the wrong thing is greater than the reward for doing the right thing, then there really is no reward for doing the right thing.