Time out from memories; they can work against the here and now if they dominate. Not that I'd get all cultish and privelege the art of 'being there' over daydreaming and reminiscing either. I fail to see the intrinsic value of focusing utterly on what may be a featureless landscape of the familiar.
We seem to be able to snap out of our reverie if the situation warrants it, in any case.
Speaking of overlong sentences: a commentary on Prong
Parental guidance before you venture to the band list on Death Metal.com (no, this isn't a memory trick; you wouldn't want to commit this list to memory).
It's a bit rigid, pardon the pun. And black metal seems to be a Nordic thing chiefly; a harking back to pagan roots.
You might wonder why the sudden fascination with different types of metal. It's true; I found heavy metal in the main to be ponderous and showy; clamouring over what was little more than whimsy. The fast jaunty pop stuff with the political or social edge was what got me going and I 'graduated onto the harder stuff'. But never HM - I would listen to The Swans or Flipper in preference to David Coverdale's Whitesnake.
I like a bit of blistering speed in my music at times, which is why Paranoid by Black Sabbath and Ace of Spades by Motorhead are such faves. But that doesn't explain Flipper or The Swans or the Butthole Surfers, who can all be slower than wading through molasses.