A friend of mine posted this elsewhere. Funny stuff!

1. Tell them every metal band worships the devil.
2. Ask if all black metal bands are trying to copy KISS or just most of them.
3. Hide their joint under their library card. (note from me: we have library cards?!)
4. Ask if they know of any other cool bands like Slipknot.
5. If they're listening to metal, tell them it sounds like some mainstream band. Doesn't matter who.
6. Say it's all a ripoff of Iron Butterfly anyway.
7. Ask if they've given their souls to Jesus yet.
8. Vaguely imply that you're gay and would like their company for the evening.
9. Record over their Cannibal Corpse albums with other Cannibal Corpse albums and see if they ever notice the difference.
10. Refuse to accept their fake I.D.
11. Ask how much Dio got paid for his role as Stuart Little. (ouch!)
12. Use the phrase "cookie monster vocals" and act like it's the funniest, most original thing you've ever come up with.
13. If they're listening to metal, tell them "These guys don't have talent. Now, those guys have talent!"
14. Say "What is vinyl?"
15. Point out how stupid Manowar is. If they agree, which they shouldnt, tell them the only thing more stupid is Black Sabbath with Dio.
16. Tell them it all sounds the same.
17. Admit that Cliff Burton was a dirty hippy who had already peaked musically.
18. If they say they love 80s metal, ask them what ever happened to Poison.
19. Tell them you like underground music too, like Godsmack.
20. Point out that Tarja from Nightwish can't sing.
21. Insist that Emperor videos would be better if they used a dance troupe. (I love this one )
22. Ask if Mayhem is Marilyn Manson's band.
23. Divert their CD shipments to the local Jewish community center.
24. Write "God Loves You" on their Venom backpatch.
25. Point out that just about every genre of music has an underground with bands who have integrity, so metal really isn't that unique. (ouch)
26. Post under their nickname on a power metal board and say Ray Alder sh*ts all over John Arch.
27. Take out the Iron Maiden disc and put in 50 Cent.
28. Give them a spiky pop-punk haircut while they sleep.
29. Pronounce "Celtic Frost" correctly.
30. If they're over 25, say that people can still rock even if they have an unplanned child or two and drive a grocery getter. Then point and laugh.
31. Tell them you're not hiring and to try the other Cinnabon down the street.
32. Sit quietly and applaud politely at a metal show.
33. Make them be sober for five whole seconds.
34. Ask if Randy Rhoads was on the same flight as John Denver.
35. Tell them Korn brought metal back to life in the 90s.
36. Turn the bass way up on their stereo.
37. Laugh at Slayer for stealing their name from the Buffy show.
38. Call Doro fat. (hey! What a load!)
39. Call them on their horrible grammar and/or spelling.
40. Remind them that metal is partially derived from the blues. Then accuse them of being widgets.
41. Use the phrase "balls in a vice" at least three times when talking about classic metal and/or power metal vocalists.
42. If it's a guy with long hair, address him as if he were female. Don't correct yourself about it.
43. Be impressed with how much RoadRunner Records has improved over the past ten years.
44. Say you love Metallica's debut, The Black Album. (lol!)
45. Notice that Lemmy hasn't moved his left hand in 30 years of playing bass. Haha.
46. Refer to metal as "that kill-your-father rape-your-mother stuff." (note: I guess that's a takeoff of "Kill Your Mother, Rape Your Dog" song from Dying Fetus?)
47. Ask them if their favorite band is so good, how come nobody has ever heard of them.
48. Pine for the good old days when Pour Some Sugar On Me was a big hit.
49. Tell them you used to be a metalhead, but grew out of it when you started listening to more intellectual stuff like...
50. Post a list of "Ways To Annoy Metal Fans" knowing full well that so many of them internalize everything and can't take a joke. (just jokes, guys! They're just jokes! )

some other things (personally)
1) Jumping about and moshing fans who just bang into you, who then you have to beat up for being really annoying cause you came for the music not the violence

2) Asking if metal is like "Metallica or Nirvana"

3) Saying "Black Sabbath were the first metal band"

4) Say "Iron Maiden are really good" and expect to get credit for knowing them and the like of!!!!

5) Saying "metal was 80's music" and that we are "tuck in the past"

6) Saying "no-on listens to that music anymore"

Hmm, lets see (somethings personal other things just from observation):

1: refer to Judas Priest as "80's butt rock". This happenned to me the other day when I was wearing my Judas Priest jacket. Endearingly so, yet it was still quite annoying and did manage to piss me of.!
2: Saying that Nirvana "killed metal".
3: Considering yourself witty when you say, "all maiden did was gallops!!"
4: Saying Venom isn't black metal, even though they fucking create the god damn genre, and those fucking lyrics they were singing on "black metal" was about their own fucking sound, not some scandinavian twats.
5: Shout "Metallica!!!!!!!!!!!!!" everytime you walk near them, as they think that this somehow pleases you, even though you have always at-*test*-('")ed that you do not care for Metallica much at all, and have named a hundred other bands that would be much better suited for shouting.
6: Demeaning doom bands by calling them "Sabbath clones".
7: Try to appear knowledgeable of metal by randomly using the adjective of "swedish melodic death metal" in a sentence.
8: Everytime a metal guy is playing a song, say how much it sounds like Metallica, even if it's fucking Exciter.
9: Use the phrase, "hardcore metal" to refer to "extreme" or 'kerazay" metal.
10: Ask them, "dont you ever get tired of listening to all that stuff over and over again? "
11: Rave about 3 inches of blood and how it's so great to see a "true" "heavy" "metal" band getting popular again, and that Roadrunner is the one who released their album! WOW!

I don't find too many guys who get mad over this one!