I am a huge fan of doom metal (stoner in particular) and I don't smoke weed all day as I listen to music. I don't smoke weed at all, infact. I also dress normal and I am pretty sure I'm not a douchebag
The worst "fans", period, are people who don't have an open mind about other genres of music and only stick to what they love the most. I love all types of music and I am always open to new bands/artists, regardless of what kind of music they create.
Just to make a friendly note, Darkest_Hour, you don't listen to anything but metalcore so it's not really fair of you to discuss other people's music tastes when you don't venture out of metalcore and give anything else a chance at all. I think the problem might be that you haven't found the right bands to listen to. I once hated power metal but I stumbled onto a few good bands. You just have to look in the right places.
If you need recommendations, I have plenty, but don't write off a genre of music when you don't even listen to anything but metalcore. I don't enjoy metalcore at all but it might be because I haven't found the right bands yet (and don't bother recommending any of the ones you like, those are the ones I hate the most, lol).
Maybe there is a metalcore band out there I would like and maybe there is a doom or power band out there you might like. It just makes no sense to disregard music when you only listen to one genre.