I put mud flaps on, and made them so I can remove them when I go on the trails.
There have been many times here in the PNW when the rain has come down in buckets when I'm on the freeway. Or driving through the wet, sloppy west side snow we sometimes get here in the Seattle area. And when a rig is in front of me that doesn't have mudflaps, it can make for some serious white knuckle driving.
When I think of folks that these kind of conditions can scare the crap out of, that aren't prepared for the extreme conditions like the elderly, and/or the non-savvy drivers who have just as much right to be on the road that I have, I can't justify my own selfish reasons for not wanting mud flaps. So I made some removable ones for the front, and will do the same for the rear. Yes it was/is a P.I.T.A. for me, but it's not about "me", that much I know.