I mess up more when I look at the keyboard. We had to take mandatory typing/computer classes in elementary school, so it's easier for me to not look at the keyboard as I type because that's how I learned.
I typed this entire post without looking at the keyboard. It's not so hard once you really get used to where the keys are and stuff; I can do it pretty quickly and easily with proper grammar.
Of course, though I never learned to type "properly" so my hands fly around the keyboard like two cracked-out spiders rather than resembling any sort of cohesive key pressing.