Man, why the Joey/Rachel hatred? He's dim, she's shallow, they both think they're God's gift to the opposite sex... it's a wonder it didn't happen earlier.
And it was obviously going to be a temporary thing - did anyone honestly think they'd end the series with the Ballad of Ross and Rachel on a down note?
Really, when you have six main characters in a light-hearted relationship comedy where none of them would ever do anything to really
hurt any of the others and two of them have already been married off, you're limited to either mismatched pairings (if you hated Joey/Rachel, imagine Ross/Phoebe!) or bringing in randoms from outside that nobody watching really cares about (Mike).