Credit Card companies are excellent at tricking you to take more of your money:

First they push cards on you and encourage you to use them. Second they find many ways to charge you fees and of course carry a very high interest rate. Third they encourage you to borrow for longer by making the "monthly minimum payment" a very small amount that decreases as you pay the debt down. With revolving debt like credit cards the amount you are actually paying down the principal decreases as your minimum monthly payment decreases. This is how they extend the time your are in debt and maximize the amount of interest they collect from you.