For years I was a wide angle junkie, living at 24mm and stitching to get wider (no money for.an ILC). Then I got my X100, and I've been using that as my main camera ever since. But I still have the 24mm history, telling me the 35mm is 'a bit tight'.
It is, however, a perfectly unspectacular focal length, in the sense that the viewer neither notices a particular wide angle effect,* and unlike a 50mm already does, there's not automatically a 'picking out details' effect either, you have to work for either 'look'; if you don't, you'll have a focal length that just registers, without either saying 'look at all the things out there' nor 'look at this particular element'. Without thought put into the composition, it can be dangerously boring, unlike wider or longer focal lengths which either show you a bunch of stuff or spectacular angles, and unlike longer focal lengths, which tend to have a subject no matter where you point the camera. But that lack of outspokenness also allows one to change between the advantages of wide angle and "normal"** more easily.
One other thing I like about 35mm is its capabilities as a 'recording one's own experiece' focal length. For instance, at 3x2 aspect ratio (1", APSC, FF) and in horizontal orientation, it's pretty much the longest focal length that will allow a torso + face shot of the person sitting on the other aide of the table from you. For 4x3 aspect rations that would be 40mm, which has the same vertical angle of view as 35mm on 3x2 sensors, but obviously less width.
Having said that, becoming acquainted with Saul Leiters work really made me appreciate (considerably) longer focal lengths, and I've been wondering if I wouldn't be better served with something in the 40 - 50mm range as default. Unfortunately, the funds to experiment with different cameras and lenses are absent and probably will be for some time.
* I know that 35mm was long considered wide angle and, in the early days of zoom lenses and digital compacts, was often the wide end of standard zooms. But I started getting serious about photography with a camera that started at 24mm, and that obviously changed my perception. Also most phone cameras have something in the 25 -28mm range as (main) camera.
** I maintain that if there is such a thing as a 'normal' focal length, it's in the 60mm to 80mm range, but that's another matter. 50mm became the default lens on Leicas because it's good for group portraits and the Leicas were conceived not as photojournalists' dreams, but as family snappers in an era where group portraits were the thing to do on holiday. That, and it being cheap to make, and pretty versatile, led to this being considered the "normal" range. So long as no one claims that it 'matches human vision', I will leave it at this and not start a far longer rant.