In a lot of sweater patterns, the instructions are to knit the ribbed edging for the sleeve cuffs and the body of the sweater on smaller needles, then switch to larger needles for the main part of the sleeves and body. This gives nice fitted cuffs, keeps the drafts out, etc.
But what happens if the ribbing is knit on the larger needles? Does it looks weird, or is it just a little looser? I happen to like sweaters that have rolled edges or straights hems, so maybe looser ribbing would look cool to me, but so far I've always just followed the pattern and done it on smaller needles. Have you ever tried it on the larger needles, or seen it tried?