I used to shoot pretty much everything.
Then, I realized that I never looked at what I shot, and started thinking more about the way I use the camera.
Now, I usually only shoot things which are interesting and unique. Pictures which contain some kind of contrast or irony. The common, but from an uncommon perspective. I'm still a bit timid about taking a stranger's picture, so it's mostly landscape/architecture/wildlife/cars/signs...
Also, I prefer relatively stationary scenes so I can take my time to get the perspective and framing right, select the correct aperture, and evaluate the scene properly.
It helps that I switched to a film camera with manual focus and frame advancement/shutter priming. The camera forces you to do the work, and to take that step back and think about what you're doing.
My output has dropped drastically, but I feel that a few of the pictures I take are worthy of being framed, are showing something that is interesting to everybody.
I simply grew old of just documenting everything I see. Taking a picture of landmarks is so pointless, when there's tens of thousands of those. I'd rather focus the time I have on holidays or trips to focus on what I see, than waste it on looking at everything through a tiny little prism/mirror.
I suspect that if I find the right muse, I'd also get back to photographing people again -- the right people are always worth of being framed, and a subject you know well is very useful, as it allows you to know the expressions you'll be working with.
Another factor is that when I carry the camera, I often look at things in the context of whether it's a good shot, which becomes a burden (more so than the weight/bulk of the camera) when you're exploring places you don't know, which you just want to take in as they are.