Kvantum said:
Mechanics. Story I can write, but it's balanced mechanics I have problems with.
This is precisely what I was going to post, but using slightly different words.
I like to write the fluff for myself. That is why I write the story hours here. Want to read a tale about a Duskblade, Favored soul, Wizard, and Psion? See my sig. You'll get my interpretation of crunch without seeing any of the crunch. [Seriously, take a read. There are two stories there, the first is complete with about 180,000 words while the second will be about the same length when it is finished.]
I don't buy fluff books. I
do read them. I usually pick them up at the book/game store and rifle through them, skimming for cool ideas. Then, once I've gleaned the five (or ten at most) really cool ideas contained within, I put the book back on the shelf, buy a crunch book, and go home. I tweak and mold the cool ideas from the fluff book until the fit my world the way I want it too.
The fluff is fun and easy for me to come up with. It is the crunch (actually, it is the ensurement of balance) that I struggle with. If someone else can do the crunch, I'm a happy man!