Most guys love their girls in pretty much anything. 😊 Well, as long as the outfit isn't either of the two extremes: too trashy (think J-Woww or Snooki circa 2012) or too tomboy-ish (think Ellen DeGeneres). They usually expect us to dress for the occasion, so maybe jeans and a tee when we're lounging around at home, a fitted dress and heels for a fancy dinner or party, and a flattering but appropriate dress/skirt for hanging out with their family.
For any occasion/time, though, I think most guys would agree that simpler is better. They like seeing us get dressed up and made up, but I think we ladies underestimate how much our boyfriends like seeing us with minimal makeup and in basic yoga pants. Plus, fewer layers means easier access if they want to get busy. 😉