The two part-episode Beach and Jellyfish was a crucial character revealing moment in the series for all except Joey.

Basically, what I'm trying to say is it speaks volumes to the lack of involvement that the writers had for the character Joey Tribbiani to a point where in these particular episodes centered on Phoebe everybody else had something deep revealed about each of them as well crucial things that will come back later, for everyone except Joey Tribbiani. Meaning if something came up for Matt Le Blanc and he was unable to make it to the set for that two-part episode of friends, very few of the viewing audience would notice that Joey's not in these two episodes. Let's see what was revealed for everybody else:

1. Phoebe's mother is actually alive and well and living in a beach house.
2. Chandler always harbored deep feelings for Monica. Monica feared she would grow old alone as an old maid.
3. Rachel and Toss both take turns breaking up with each other.
4. Joey is just Joey.

In both episode TOW The Beach and TOW The Jellyfish, he was really only seen tagging on with others like hiding under Rachel's giant sunhat with everybody else, or being present with Monica when she got stung by a jellyfish. Joey wasn't given anything to do on his own except get drunk on margaritas and fall under the table.