I had one of those Citibank Platinum Dividend Cards. I accepted it because it offered 5% back on grocery, drugstore, and gas purchases, on a maximum of $6,000 per year. They canceled the program partway through the second year I had the card. At first I thought they'd canceled it just for me, because I hadn't racked up any interest or late fees. So, I googled and found that, indeed, they really did cancel the program. Then I went out and bought a couple of grand in grocery gift cards in order to reach the $6,000 limit for the year before the mid-October deadline.
I figure Citibank lost several hundred dollars on me, since they'd rebated $600 on $12,000 in charges, but earned only the two or three percent (maybe less) they get out of the merchants.
Fortunately another bank is offering the same deal but with Master Card, so I continue to make money.
Capital One tried to issue me a $25 late fee on a $5 balance (I paid the account a week early but forgot about a grocery store visit I made after I paid), so I bitched at them and they waivered the fee (dropped them anyway). If you righteously bitch at them, they will often waiver the fees. They can't say much to you if you have a record of paying the balance every month. On the other hand, if you carry a massive balance, you make yourself a slave, and they're less likely to listen to your complaints.
Not a very hard decision to make...not very hard at all.