I am fascinated at how credit cards are both quite a good deal and a very bad deal at the same time. If you use them right - which is mostly pay off each month

I am fascinated at how credit cards are both quite a good deal and a very bad deal at the same time. If you use them right - which is mostly pay off each month - you can get nice sign-up bonuses (up to $600 is not unheard of if you're lucky), you can get 1.5-2% back on every purchase and 5-6% on selected categories, and if you're careful, you can also take zero APR longer-term loans with some credit cards (provided you pay them off properly) which helps structure unexpected spending like major appliance breaking down. On the other hand, you get unbelievably bad deal with 20+% APR if you don't use them right, and on top of that various fines for not paying on time, so if you get the wrong end of the deal, you can pay 2x-3x of the original amount. One of many things on the credit market which makes your life much easier if only you can prove you don't really need their service.