Part and parcel of a Bethesda game is going under the hood and tweaking with everything in sight. And surprise: Fallout 4's no different. If you're playing on PC, it's almost mandatory to muck about with the game's .ini files. Hell, you had to do it with Fallout 3 if you wanted to get the game to stop crashing on Windows 7.
Of course, that's not necessary with Fallout 4. But if you want lots of nice things, including an unlocked frame rate, adjustable FOV, no mouse acceleration, ultra widescreen support and the ability to skip the intro video ... then you might want to read on.