I always thought that Bach was thumbing his nose at all keyboard artists with the C-major prelude and fugue from Book 1. The prelude is so simple, so lyrical, and he lulls you into this "Hey, I can do this; how bad can it possibly be?" attitude.
Then - WHAM!
I learned the C-minor prelude first (it's got some character to it, especially if you don't play it like a typewriter). Then I did the C-minor fugue. I still stumble over some of the 16th note scales every now and then, but it's a pile of fun to play.
I remember someone saying that the hardest fugue of all is the first one you learn.
How true!
It took me about 2 months to (sorta) learn the c-major fugue, and I still don't have it committed to memory. It was worth the effort. It's the perfect companion to the prelude. It's lyrical, crystalline and pure. Every now and then when I (poorly) play it, I still get a chill up my back from the beauty of this music - and it's a FUGUE!
Learn it slowly, following the advice here, and you'll learn to love it as I do.
George
(now working on the G-minor prelude and fugue from book 1)