No, I mean specifically that it's very hard for me to figure out how to design a visual interface (although I usually have enough taste to know a good design when I see one.) It feels like the best I can do is just try a bazillion layouts and weights and colors until I find something that happens to look good. I suspect that if I could sketch out designs competently it would help me both imagine things more clearly and mock them up, so I can arrive at something passable quicker.