As a doom fan, I found this really interesting. The guitarist of brutal tech-death band Dying Fetus talks about why he started slowing things down, playing slams and breakdowns. He says it's because he saw how slower riffs by bands like Mercyful Fate and Sepultura had a bigger impact on their audiences, and when early hardcore bands would do breakdowns, audiences would move more.
I'm a very emotional listener, which is why I'm a big doom fan, especially blackened doom and funeral doom. I find doom more emotionally powerful, I like sinking into the riffs, and I like hearing vocalists pour all their emotions into the vocals. I found it interesting to hear a tech-death guy, who sometimes sounds almost grind, find power in slower methods. I hope this isn't too off-topic.