To you, downstairs neighbor with a thing for extra-loud death metal at all hours:

You:
You are the kind of guy who bikes to work, and holds the door open for your neighbors. You're well-groomed and wear trendy dark clothes. You are slightly creepy looking, but you're normally smiling while you smoke your cigarettes outside the building, so that somehow makes you okay.

However:
You need to start saving up for some really nice BOSE, noise canceling headphones, maybe even some that are Bluetooth compatible. Because, dear downstairs neighbor, your taste in music is just really not ours'. We like you, we think, but we don't want to listen to your crappy, base-drum driven, repetitive, growling, floor-vibrating choice in music. Even the dog seems annoyed. She's moved from sleeping on the rug to sleeping on the chair, a few feet and several foam-insulated layers away from our floor, your ceiling, dear downstairs neighbor.

Please:
Just turn it down. Your choice in music sucks, but that wouldn't bother us if it didn't make the liquid in our glasses quiver.

Sincerely,
your normally mild-mannered upstairs neighbors, and our dog