Players from another worlds - why?

[Bixby]

As for why they were rude? Different servers have different cultures and player attitudes. Yesterday I was paired with a Blackmage from Balmung(one of the unoffical RP servers) for T7. He had macroed messages to every single one of his actions making him spam party chat with what amounted to announcements that he was casting Fire.

This is the question the OP is actually asking, and this is a good portion of the answer.

It's also feasible that they've checked to see if you're from their server and, if not, decide it's not a big deal to be a bit more rude. I have a hard time believing that, personally, but it's a possibility.

It's also just dumb luck and confirmation bias.