When Emily calls, Ross hangs the phone up and then hits the button for the speaker, but the call would have been disconnected when Ross hung up. He needed to push the button and then hang up.
When Ross says that he and Emily are getting an apartment near Columbia University, Joey complains that "that's three trains away!" Columbia is on the #1 (and, at that point, the #9) line, the same subway line that's the closest to the apartment on Grove and Barrow. Joey (and anyone else) would only have to take three trains if he switched from a local to an express and then back to a local.
(at around 8 mins) When Danny slams the door to his apartment, the adjoining wall shakes.
Phoebe doesn't want the coat because it is an animal product but earlier in the season she was fine receiving leather pants as a present during her baby shower.