I ALWAYS worry about pooling. I ALWAYS worry about whether it will horizontally stripe. I ALWAYS worry that what looks great in the skein will look muddy/crappy/disappointing/ugly when it's knitted up. I've never understood why yarn sellers don't show a swatch rather than just the skein. The swatch would give me sense of what I'm thinking about buying.

I also always wish I could get sweater quantities of hand-dyed yarn (like 2000 yards or more). There are only to many mitts, socks, hats, and little shawls a girl can make...