To quote your signature...
"I don't understand what your
idea of 'Uninteresting' is."
Seriously, your wallpaper is vastly superior to Shark's. Sure, it looks calming, but yours is better for the following reasons:
You didn't have to edit your wallpaper.
Your scene contains characters; Steve, a Wolf and an ENDER DRAGON. Shark's scene is empty.
Your image is in PNG format so the quality is retained, unlike Shark's JPG, where details become grainy.
The lighting in your scene actually makes sense. Shark's scene appears to have two conflicting sources of light from behind and in front of the camera, whereas in your scene it's easy to see sunlight is coming from the left.
I know there are some aspects you can improve on, but that's the point. Practice makes perfect! You shouldn't put yourself down like that, because your wallpaper is actually really good. As for the lack of Upvoting, bear in mind that not many people view these in the first place. I looked at the "Wallpapers and Art" section and in the past week, as of typing this, only 5 out of the 29 topics have more than 100 views, and two of them are memes, one is a question and another one is a gif.
Just remember that if you're getting Upvotes, you've done a good job. People like what they see.