Ugly is a broad category and without some qualifiers many bikes could be considered ugly for several divergent reasons.
A bike could be ugly only because the aftermarket accessory porta-potty unit fitted to the bike throws off the aesthetic balance of the bike as a whole.
Another personal judgment call would be to consider a bike ugly because the frame and sheetmetal do not contribute to a pleasing overall effect. Early 50’s Shelby airflows, much like the Cheeto’s bike, have been singled out and derided by some in previous threads on this site for that reason. Similarly some factory and some home paint schemes and colors are not to everyone’s taste.
Or; a bike could be considered ugly just for having more or less patina than is preferred by the observer. This seems to be where many of the posts so far are coming from featuring bikes that look to have been left to the elements too long.
Lastly, I suppose, bikes could be deemed ugly for just possessing a mean streak. I have a MK IV Jag that I refuse to ride anymore because the 3-Speed has a nasty habit of shifting into neutral at exact the wrong moment.
Oh, and Dave, your engraved invitation to LeMay (for you, your girl's Schwinn, and one guest) is in the mail. Please remember to empty the holding tank before arriving at the event as there are no sanitary connections available at the Concours.