Trying to deal with the Chipotle Rewards program recently had me pretty steamed.
I had enough points for two burritos, so I redeemed the points. Then when I went to place my order, I found out that (for no reason) you can only use one reward per order. I was annoyed but figured no problem, I'll just save the other one for my next order. But since I had now "redeemed" the reward, it had a very short expiration date. So I had to order Chipotle again a week later, which I'm sure is exactly what they wanted.
The whole reason we were ordering Chipotle in the first place was because there was a school fundraiser. I couldn't find the place where you enter the fundraiser code. After much research, I finally figured out that they don't let you use any rewards if you're doing a fundraiser (why?). So now I had to skip the fundraiser.
I also observed that if you use a reward for an item, and then you add a cheaper item to the order, it immediately "swaps" the reward so that it applies to the cheaper item. Now I had to change around my order to avoid getting taken advantage of.
Notice that for all three issues noted above, Chipotle forced me to change my behavior to deal with their rewards program. I think a good and honorable rewards program should give you a free item without having to be coerced into doing what you didn't want. I've never had this sort of problem with Chick Fil A, for example.