Depends on which pill, and also how old you are.
If you are still growing then not taking your Cortef will cause you to start growing too fast, and use up growth too quickly, which will result in you being short as an adult. Whether you're still growing or not, not taking your Cortef would leave your body without one of its most important weapons against fighting the stress of injury or illness. Ypu might feel fine for awhile, but eventually something will happen and the medicine you need won't be there, and you can very easily die.
If you don't take the Florinef, then your body can't balance the salt levels and there are very negative side effects to that, too.
I have two kids with CAH, but am only a carrier myself. but I do take medicine for seizures. When tyhe doctor first prescribed the medication I was just out of high school and the seizures were very mild, so I decided I didn't need to take the medicine. I had a grand mal seizure not long after that. That big siezure did two things. It set up patterns in my brain which made me even more suseptible to seizures, and it put me on the list of people with serious seizures, that means I have to keep getting the doctor to OK me to drive, ever few years. Taking the pills is no big problem, but ultimately not taking them became a big problem. Not taking your Cortef and Florinef is much, much more serious.
How hard is it just to take the pills?