It depends on your job. If you level paladin, ninja, or bard, you'll never want for invites. By the time the yanks go to bed, the Japanese are up. If you want to level Thief, on the other hand...well, take heart in the fact that people aren't passing you over because you're British, they're passing you over because you're a Thief.

(<-- THF75, levelled pretty much exclusively during JP hours )