Removable, peel-and-stick subway tile. The kind you can install over your existing tile in an afternoon, without any special tools or tricks. It sounds like the stuff legends are made of, doesn't it? But it's real, you guys. So real. Check out Smart Tiles.
Smart Tiles aren't actually tile, but a thin sheet that sticks to a surface and replicates the look of tile and grout. They're made of a special gel material, so they're shinier than regular tiles. By all accounts (what I could find in comments and forums around the web), that unnatural sheen does seem to give away their secret. But I think a little shine is a bunch more tolerable than living with a kitchen backsplash that you hate. Plus–sound the trumpets–they're removable.
Anna of Door Sixteen recently did a big round up, finding examples of Smart Tiles out in the wild (check out a whole bunch of photos here). And, yeah, they actually look pretty damn good. At the top of the post is a shot of the Hexago pattern in L'atelier de Curiosité's kitchen, and directly above is the same pattern in a before-and-after look at Carnets Parisiens' backsplash makeover.
The Smart Tiles website states that their self-adhesive tile will stick to any clean, dry and smooth surface (including existing tile). They're heat and humidity resistant, too, so perfect for the kitchen or bath (to cover your hideous existing tile).
Re-edited from a post originally published 8.17.15-NT