You're both right! It took us 4 years to decide on a BS for our kitchen, so we just painted the walls with an extra coat of paint, and it was fine. However, since you have such a neutral vanity and mirror, you could really add some punch with a fabulous tile and it wouldn't cost you much. I would just do the few inches between counter and mirror and carry it along the side wall. There are beautiful white textured/embossed/patterned tiles out there that you could really have fun with. Here is a link that might be useful: textural white tile backsplashes

That sounds like a good idea, but, the edge of the countertop is slightly raised from the rest of the countertop. I think if I scribed off the edge of the countertop it would look funny, also if I fit it into the drywall it will look goofy also because that raised edging will be absent on that corner...it will definitely look unsquare. Thank you for the ideas tho! Any other ideas??

the white trim prob wouldn't be much higher than the granite. (usually 4") So, if you really want higher, you could see about doing some decorative thing to make it higher, but not sure how that's going to look. A good bathroom paint on the wall, and vinyl trim piece with equally good enamel paint, should be impervious to your splashings! (I would have done a wall mount faucet. much easier to keep clean) then you could have had the granite come up about 9-10 inches. or, you could do something like this i would have forgone the wainscot on that wall and just done the tile one last pic w/the wainscot. the trim piece sits a bit higher than the countertop piece. take you pick of what you like.

If you’re not worried about the wood counter then I’m honestly getting a wallpaper vibe. Something with a white background and a lot of negative space, maybe a large scale print. Not really busy, but whatever your taste is (floral, geometric, striped) and then look for a simplified version of it. I also like the idea of wide panel woodwork, vertical or horizontal, because I think it would contrast nicely with your tile. You can definitely do a tile backsplash but I think it’s a little more complicated on the vanity wall next to the shower because you have to choose more carefully. Since they are next to each other, there’s the consideration of how much of the wall you do in relationship to the shower, and then consider the other vanity. I think you can be more creative if you opt to do something different altogether. I’m not a huge fan of accent niches but honestly as far as they go it’s a good choice! A white wallpaper with some kind of fineline black print would look great with the tile and the wood. Something about lower tile back splashes right against a full tile wall is a little harder for me. I’m having a hard time with this one in one of my projects and I have found I generally like switching materials altogether instead of breaking up the wall. Also, i love bathrooms with little quirks and I have a feeling whatever mistakes you made you will still love this one in 20 years.