I like color, and I like the background to not be too “busy”. Black causes too much contrast with icons and other screen elements for me, and a busy background is distracting and makes it harder to pick out icons and such on my desktop. I also use switchable workspaces. Since I’m WFH there’s a couple for work and a couple for personal stuff. So one desktop rotates pictures daily, one desktop always has a picture of the building where I (normally) work, and a couple others have solid colors. Special shout out to Digital Blasphemy for two decades of cool desktops (I’m a paid member).