Live and learn
Shamefully, I was well into my thirties before I realised that you're supposed to move a vegetable peeler back and forth over a carrot, not straight down over and over. Because it's, you know, sharpened on both sides.
In my defense, my grandmother was well into her fifties and she still used it like a knife: one single stroke over and over, scrape scrape scrape. Not the brightest bulb in the box, bless her.
Then again, it doesn't say much for my own IQ that it took me so long to suss it out either.
Q
Darwinian challenges posing as everyday kitchen utensils, lesson 101
EDIT: Hrm. Judging from the bulk of the comments, it seems to be more of a preference thing, or a left-or-right-handed thing. Your thoughts?