When Pheobe and Rachel first have discourse regarding which of them will be Monica's maid of honor - Pheobe tells Rachel that she's never been a maid of honor. This goes on to influence Rachel's decision to let Pheobe be Monica's maid of honor. Later, due to Joey's unintentional interference, Rachels learns that Pheobe has already been Maid of honor twice and lied to Rachel earlier. This directly contradicts a conversation the two girls had in the beginning of their friendship, in Season 01, when Pheobe sits Rachel down to warn her about her then fling, Paolo. Phoebe begins by explaining to Rachel two things: 1 - She never lies to her friends, and 2 - She makes the best oatmeal cookies.