I tend to classify things by how I'm going to use them. This is why my computer is so disorganized. I want to put things where I expect them to be. I want to put things together that I tend to use together. This means I set the policy of sorting files not by their content, but by their intended use at the time I created or saved them. Is that a drawing of an anime character that doesn't have any other specific purpose? It goes in an anime fanart folder. Was it inspiration for a possible character in the story series I wanted to write? It goes in a subfolder of "story". Did I think "I'd want an action figure looking like that?" It goes in a toys folder. I set this standard precisely to make such situations easier: so I wouldn't have to do the tedious job of writing up the purpose of every saved image, letting its location do the talking. The problem is that my projects and concepts tend to overlap and converge, so the same file ends up relevant to multiple locations. No, duplicating it isn't a solution. That just confuses me. So for a long time, I've frequently not known where to put most images at the time I save them.
Now, how this relates to deviantART...
I spent a lot of time browsing here for many years before I joined. Two main reasons for being a member:
1: Access to ecchi-er stuff. Yeah, I still look for that here, but after a while, I started spending more time looking for that elsewhere (particularly Tumblr) and less here.
2: Wanted to get into anime fanart, etc. Needed a venue and some motivation. Didn't happen. Other unplanned life events destroyed my motivation, and my anime/manga fandom has declined anyway.
I do certainly look for other stuff, but it should be evident from my favorites that subjects related to those make up much of my activity here. I do have other interests, but internally, I appear to have classified dA as part of my anime/fanart/etc interest.
Railroads are a much longer-standing hobby interest of mine. I use many other railroad-specific sites, so it's not a priority to look for trains here. I also feel hesitant about favoriting any railfan photos. Maybe it's because I don't see them as art, at least in the same way the other art I favorite is art. I do a lot of railfan photography, and I don't perceive myself as an artist. That's simply not my goal in it. But anyway, the reason I don't favorite more railfan photos is related to that, but slightly indirectly. I have no standard of judging them individually, and because I haven't looked at enough of the railfan photos on here, I don't feel like I have favorites.
And thus, though I see other people putting railfan photos on here, I haven't felt motivated to do that with my own. Maybe it's because I'm already uploading them elsewhere, and I haven't felt the need to duplicate a small number of them. (Uploading everything would be a huge flood suited for an image host rather than an art site.) Maybe it's because I'm embarrassed about having an empty gallery, but since my intended purpose was animanga art, photography wouldn't feel like it fixed that.
I'm hoping that posting this motivates me to do that anyway and have something in my gallery before I hit the two-year mark here.