Oh my Goooood. I just saw what you did there.. I was about to go all, "What?! Yeah, you're awesome!" but then I re-read your name and now I'm involuntarily facepalming again. Seriously, while typing, half of my vision became blocked and I noticed my hand placed itself on my face by itself. Again, I say, well done.
White clothing stains easily, and it costs a lot of money for cleaners to get stains out of white clothing. Luigi's original sprite in Super Mario Bros. had green and white clothing, but in the following games, he wears blue overalls and a green shirt.
The joke is he changed his clothes because it's cheaper to get stains out of regular denim overalls.
Last I checked, said crabs, flies, and turtles weren't that difficult because Weeg had Mario with him 24/7 (only way he could have been there. Player 1 can't play Luigi :/). The beasties, bullets, and bigger turtles all just seem worse because big bro isn't always there to help out. It's all just a matter of perspective. ~Something's gumming up the plumbing; poor Luigi's in a bind. Giant Turtles out to get him; creepy crabs are right behind. Fighter flies, jeeper jipes, something's coming up the pipes...~