Utterly Mad

Granted, you travel back in time to the late viking age, roughly 1000 AD or so. Great! Except it doesn't transport you in space, so no vikings for you.

Best case scenario the wish-granter is a smartass and maintains your relative position on Earth, which presumably leaves you miles upon miles away from fledgling Coles Creek culture, the cultures of the Pueblo II period, or any other major civilizations. On the plus side, you're a couple hundred years early to have to worry about the Triple Alliance, nevermind how long a walk south it'd be.

Worst case scenario, the wish-granter is too literal and you get dumped in the middle of space.

I wish for a personal teleportation device.