My wife doesn't understand what how I/we can listen to metal or how we can put so much energy into talking about and spending so much money on CDs. She doesn't mind some of the stuff. She dug Opeth, somewhat, when we saw them live. She thought Arch Enemy was funny simply because of Angela. She loved Angel Dust, not because of the music, but because it was an energetic/entertaining performance. She even went to go talk to the singer after their set.
But stuff like Nile and most black metal, she doesn't understand what we see in it. I don't know how many times we've had the how can you like metal vs. how can you like the radio discussion, but we've pretty much called it a stalemate.
She has said that the actual music is good with bands like Graveland, THyrfing, Summoning, and a lot of the more epic bands, but she just can't stand the vocals. Maybe I should get some power metal..............um, no.