I really like "classic" boats (sail or power) owned by others who have the money and time to maintain them. The newer bene's and the like with squared windows in the hull (I don't mind rounded oval ones), and light, squared and modern interiors, not so much. However, I do appreciate the design work that goes into these boats, just as I can appreciate the design that goes into some mid-century modern homes, though I don't particularly like them either.
I wouldn't consider the majority of boats out there as ugly though there are some. I've also seen some decent looking boats made pretty ugly by an owner that puts an erector set of an arch on a boat with all kinds of stuff attached to it. Kind of like an out of character, boring, ugly addition put onto an otherwise nice house.
A truly nice looking boat is one that you stop and look back at every time you leave it at the dock. FWIW, the last time we were in Maine, there were no ugly boats there (and a lot of really nice ones). "No ugly boats here" should be on the license plates in that state.