i have been purling 'wrong' for the past two years. it was causing my stitches to be oriented wrongly on the knit side... resulting in a fabric that looked kind of like it was 'weaved' rather than the usual straight lines of lovely stockinette other people produce.
if you look closely at my Simple Knitted Bodice you'll see what i mean. the top part, the shoulders, above the lovely colours of the Silk Garden was knit back and forth. you can see how it's not as straight and smooth as the bottom half of the pullover, which was knit in the round (no purl stitches).
go ahead, click on the photo to see it a little bigger.
and here's the Caftan Pullover i knit for my mother... you can see how the stitches are rather twisted looking on the purl rows.
okay... say it with me...