OK, here's my top 10 (in no particular order):
1: Cost of tires/bodies. Outrageous!
2: The "My uncle/friend/brother/father/pet has one that goes faster".
3: Nitro in general. The tuning, mess, smell, sound - all of it!
4: Glueing tires. I can never get it right. So, I get premounts and they can't get it right either (actually, they do, but they don't stay together).
5: Spending several hours cutting, fitting, painting even a basic body just to have it all scratched up in 5 minutes. Driving better would solve this, but that's not an option.
6: Nitro in general. The tuning, mess, smell, sound - all of it!
7: The LHS never, EVER, having the parts or raw materials I need.
8: Kids asking if they can try it. Yeah, right.
9: Having to mod a brand new part because it just doesn't fit like it is supped to.
10: Nitro in general. The tuning, mess, smell, sound - all of it!