What am I actually paying for?

I'm getting eaten alive by instructor fees. $100/hr is definitely above average from what I know, but it's the only option where I live. That's for ground and flight instruction. So here's my question, and I'm sure this has come up before, but what am I actually paying for when it comes to ground instruction?

Flight instruction is easier to define because you should be flying with your instructor. But ground seems to translate into paying for the instructors time with you, not for the actual ground instruction occurring during the time you're with your instructor. Hell, I just got charged $100 plus for probably five actual minutes of instruction, while the rest of it was filling out paperwork needed in order to rent a new plane. Extremely frustrating.

Ultimately, this comes down to me chatting with my flight instructor and setting some boundaries/getting an explanation. That being said, it doesn't hurt to ask for outside opinions and hear others' experiences.