The ways that credit cards can make you unhappy are legion. Fees, balances, crazy interest rates, universal default, the list goes on. But, even though we just saw Bank of America digging a pit in your backyard, and word has it the zoo is missing 3 tigers and a crocodile, there are a few ways that a credit card can make you happy. (Not all of these tips are unique to credit cards, so check to see which benefits your debit card has.)