My first impression was that the Capitol Wasteland was a bleak, dark, horrible place. A wasteland, even. I had the random encounter of people fighting a wounded Deathclaw (2nd or 3rd most dangerous enemy in the game, I think) and barely managed to finish it off before it reached me. After thatm any time night fell in the game, I would stop where I was and wait for the sun to rise for fear of running into another one, or something worse.
There's not even any relation (I think?) between enemy spawns and the time of day, I just really didn't want to wander around the wasteland at night. That was how weirdly frightening the game was at first.
A few playthoughs later, I found myself gleefully stomping through the night looking for more things to kill so I could remove their limbs and heads with a sledgehammer, or just empty a gun I didn't plan to use but had looted enough ammo for into the carcass for that little burst of satisfaction at seeing another dead thing turn into shiny, red giblets.
My favorite places to do this were next to Super Mutant gore-bags, just to make it ambiguous to imaginary passersby whether they were packing up and went to take an irradiated piss halfway through, or if the contents of the bags somehow reaped bloody vengeance upon their killers.
So, yes, the 'magic' doesn't last forever and the longer I hung out in the game, the more detached, depraved, and demented I found my behavior. Maybe there's a message in that, but until you get desensitized and no longer care about the few good/decent/not-insane people you meet in the game, there's a decently absorbing experience to be had, I think.