Ok, one pet peeve of mine is when people get dimensions wrong.
Dimensions are very important in my work-world. If something is sized incorrectly, the whole design could be screwed up, or it wont mail at the correct postage rate, or it wont fit inside the frame/envelope/display. And so on.
I hate to say this (gulp), but pretty much every time I get backwards dimensions, they're from a woman.
At any rate, dimensions can be very important - think custom shoe rack or entertainment center.
Dimensions are given width x height.
Remember this little trick....an 8.5 x 11 sheet of paper is 8 and 1/2 inches wide by 11 inches tall.
You'll never give wrong dimensions again.
(thanks for reading my little rant.)