It's torture using a tablet. Every time I get sick of how badly I draw on a tablet, I go back and draw something on paper - and it looks great.
Yesterday, I looked back through the things I'd drawn on paper, and realized something: I'm really improving. The torture on the tablet is honing skills I never realized I was lacking, and returning to the incredible ease of paper shows the improvement.
Unfortunately, that doesn't change the fact that I don't have a scanner.
Here's (full size) the image which made me return to paper in irritation. The paper sketch looks really good... but you won't ever get to see it!
It's largely the lack of instant feedback. I'm drawing on one place, seeing the image on another. Maybe I should look into tablet PCs or something.