On the other hand, I didn't want to inflict my collection of anime soundtracks on my colleagues either -- so everybody used their headphones and all was right in the world.
Due to various project circumstances, last week monday, H joined the team on the room, taking D's place. B wasn't present, and H asked about the strict 'headphones-only' policy. So I told him about B's choice of music and my choice of music, and he was curious whether this "überhappy Japanese pop" was as bad for his mental health as I made it out to be. We do have a set of speakers in the room (to be used by B when I am away), so I hooked up my computer to the speakers and blasted the album 'April' by Round Table and Nino (known from the opening theme to Chobits). To my amazement, H admitted that he kinda liked the tunes. So I put on some Maaya Sakamoto, which he liked as well.
Then B came back. I was ready to unhook the speakers, but he said that he was OK with my choice of music. So I played the soundtrack to Haibane Renmei. And they were OK with that too.
So now I have been promoted to the room's DJ, completely out of left field. I do play other stuff than only J-pop, and so far I have had only one complaint: Kraftwerk was too monotonous for H's tastes.
I wonder when it gets too weird. Maybe I should play the Angelic Layer Character Vocal album -- if they don't protest against that, then anything in my private MP3 collection should be OK...