Most of the restroom graffiti I've encountered is "Anne loves John" or "For a good time, call..." plus some random words you don't want your kids to learn. But occasionally, there are clever gems that are worth taking a picture.
Of course, it's still vandalism, and I would never endorse taking a Sharpie into a public toilet. Or a private one, for that matter. But the quality of the thoughts behind those scribbles seems to have improved in the last few decades.
See 19 masterpieces of restroom graffiti at Buzzfeed.