The rule is: however many episodes are in a season, that's how many favorite episodes you can have

• The One with the Truth About London
• The One where Everybody Finds Out
• The One where the Stripper Cries
• The One where Joey Loses His Insurance
• The One Hundredth
• The One where Ross Can't Flirt
• The One with the Dollhouse
• The One with the Routine
• The One with the Rumor
• The One with Ross' Sandwich
• The One with the Mugging
• The One where Rosita Dies
• The One with the Sharks
• The One with the Prom Video
• The One with All the Thanksgivings
• The One that Could Have Been
• The One with the Ring
• The One with Unagi
• The One in Massapequa
• The One with All the Resolutions
• The One with the Nap Partners
• The One where Phoebe Hates PBS
• The One with the Kips
• The One with the Flashback