1. Everything to 11Electric Wizard. They don't settle for brutal--they gave us Suffocation. They don't settle for fast--they gave us Napalm Death. They don't settle for slow either--so they gave us Evoken. Nothing is ever half-assed. If you're not going to go to 11, then why go at all?
2. Intense, Raw EmotionMetal has intensity unmatched by any other genre. Yes, I will agree that punk has intensity, but intense punk only deals with one kind of anger. Metal deals in so many shades of all the most intense emotions: rage, despair, hate, fear. From the terminal depression of My Dying Bride to the all-consuming rage of classic Slayer, it's out there.
3. It's HeavyNothing can top that physical sensation you get when you listen to some really heavy music.
4. Shivers Down My SpineI had a friend in high school who told me he knew a song was great if it sent shivers down his spine. (I'm certain he was talking about something off Metallica's first four albums.) I like that feeling, and no other genre of music does it for me. The song that does it for me more than any other is "To Live Is to Die". There are several moments, but if you want only the best one, start at 5:53, and prepare yourself for the part at 6:20.
5. It's ChallengingI prefer music that's challenging. If music was supposed to be pretty and easy to listen to, everyone would go around listening to lullabies. Metal has some of the most challenging music, music that forces you to pay attention and unravel something that's different from anything you've ever heard before. Meshuggah, Ephel Duath, Portal, and Ulcerate will all blow your mind.
6. EscapismSince I was a young Star Wars fan, and up through reading The Lord of the Rings in law school, and all the time in between, I've preferred science fiction and fantasy. Escapism is an important part of metal. Whether you listen to the lyrics or not, Amon Amarth sounds like Vikings going to war. Escaping ordinary life goes hand-in-hand with turning everything to 11, because real life is boring:
Fantasy is awesome:
(Thanks to That's Not Metal for inspiring the comparison between real life and fantasy.)
With fantasy, you can deal with questions of good and evil, in a large context. These are big issues, not petty concerns. I don't care about petty things.
7. VillainsA better villain makes a better movie, because heroes are all the same, according to Roger Ebert. I think he's right. Heroes are pretty boring. I like villains in my movies, and I like villains in my music. Much of metal sounds villainous. A recent favorite is Triptykon.
That's just part of the story. Why do you like metal?