I like ugly things, they are far more interesting.
In terms of lenses, it's the ugly ones, with harsh and distracting bokeh that are often appreciated the most by some photographers (Trioplan and harsh bubble bokeh lenses come to mind, as do lenses with mechanical vignetting and their swirly bokeh). These lenses create their own images in the way their bokeh draws attention to itself, and away from the subject. At the other extreme its the exceptionally smooth bokeh of cine lenses that are demanded for their very lack of attention to their bokeh, allowing the subject matter to shine. I suppose it is this later group that you consider beautiful but maybe you are using the wrong term in the first place and maybe terms like 'harsh' or 'smooth' night be more appropriate.
By the way, one of the smoothest lenses I've used is the Contax 135mm F2, very soft bokeh (behind the subject) but still very sharp, a great lens, If I find some pics I'll post them.
I would agree that "beautiful" is very subjective of course and also add that there isn't even one single rendering style per lens... as the result of the OOF look will depend a lot on the type and intensity of the light, the distance to the subject, the material/reflectiveness, the aperture and its shape, differences in background- and foreground-bokeh etc. so even within the images of one single lens you might find some where you love the rendering and others where you hate it.
Here's an example of different rendering styles from one simple Agfa "M 3525 6/3" (50 mm f/2.8 or thereabouts) triplet (another one of my all-time favorite lenses when it comes to rendering):
It can go from distinctively bubbly:
Light is key
Dan Delight
to a mixture of busy and smooth:
Winter is over... white everywhere!
Open house in hell
to quite smooth but glowy:
Feel the pain... and brush it off!
and finally very smooth:
Rad color!
https://flic.kr/p/2nqBfKF
Pearly gates
https://flic.kr/p/2npZXk3
