First you start off with no credit, so you feel like you will never be able to get credit. Then you manage to get a few smaller cards, figuring, ok, will pay these off no problem. Then after that goes well, you start getting larger and larger cards, thinking, well, if I couldn't pay them, they wouldn't give them to me. A few months go by, building up debt without even realizing it. Before you now it, you are $$$,$$$ in credit card debt and no way out.
Wow, that was a rough ride
You can get in over your head very quickly and no one is immune.
Best lesson, if you can't afford it, don't buy it.