I feel really lucky to have so many metalhead friends looking at some of the responses here. Granted, a lot of my friendships grew from talking music in the pub, I gravitated to those who were into the same music as me. Even the ones who aren't into metal like Foo Fighters, Green Day, ska punk etc. I've got something musical in common with almost every friend.
One of my friends is about 10 years older than me and before I met him he used to come into the pub wearing Megadeth, Pantera, Slayer t-shirts etc. At the time not a lot of my friends listened to 80's/early 90's metal, they were all about the newer bands. Eventually after seeing this guy (and his girlfriend at the time, who is also a good friend) for a few months I just sat at his table one night and started talking metal with him. We've been good friends for like the last 12 years
Music is that important to me that I can't help talking about it. Been lucky enough in my local area (south west of England) for there to be loads of metalheads