Bad material choice. You don't take a 30x30 material and try to cut it down to 18" high and end up with a good result. Pick a different material. And you might want to actually design it and communicate that design to the contractor next time. They are not mind readers as to how you want it.

It should have been laid out and discussed on how the veining would be handled.

Since the veins are random you maybe should have purchased extra in order to get the right cuts.

How expensive was a 30 x 30 piece? You might need to start over. Or live with it a while and see how much it really bothers you.

It would have been easier and a more consistent look to use subway or other style tile.

Poor choice of material and poor communication.

Actually we did communicate with them and then didn't do what I asked.

Have them redo it if you didn't get what you were asking for and agreed on. It isn't a terrible installation for the choice of material, the veining in that tile is going to be hard to line up without buying more than you need and actually laying out the tiles and picking the ones that line up.

I'm not clear on what you asked for (and what they didn't do). Can you clarify what your expectations were, and how they were communicated to the installer?

One tile was a perfect fit over the stove. Which is the entry. Instead they put it left. I asked them to line up some other ways too.

Wondering if they can take down one or two, then I could buy a few more, and match it up so it looks nice. Or will it look bad no matter what.

I don't think it looks bad now... again... for the material you chose. Just ask him to center it like you had talked about if being off centered bothers you.

YES acm, he would have to center it and redo the tile. They would have to get more material.

Why is the plug in sideways?

Not screwed in yet

Wrong choice of tile for this area. You'd be hard pressed to get veining match decently, and you'd have loads of wastage.
The good news is it's a small area, so you can pick another tile and redo it all relatively easily.
Also, if you don't wrap the tile around the corners, you get a better, more open appearance.
Regarding who is responsible and pays for a redo, I can't understand the extent and clarity of your arrangement with your tiler. you'd have to arrange something on that end

I don't hate it. Since it is cut into large individual tiles, it's ok not to be 'matched.'

If it were two piece and the change was sudden in one place, I'd have an issue.

Well... you picked tile. Lining up veins may never work as most prints are moved around on the tile. If you wanted a consistent flow you should have picked a 2cm marble slab. Would have been more $$ but it would have flowed nicely and given a much more clean look.
If anything, I would remove the tile and that god awful schluter trim on the side walls and just paint.

Yes, pencil tile would have looked better to finish that edge.

What is pencil tile and Schuler edge?

In the picture above it's the small tile that caps off the rest of the tile. It finishes the edge of the tile.

Your guy used a metal edging--that's the Schuler edge.