Corrected entry: In Season 2 Episode 1 'TOW Ross' New Girlfriend' Joey is talking about how his tailor did his first pants when he was either 15 or 16. He wasn't sure and said 'When was 1990?' Indicating that he was 15 or 16 in 1990. In Season 6 Episode 19 'TOW Joey's Fridge' It was revealed that in 1981 Joey was 13. Which means that Joey was born in 1968. If Joey was born in 1968, then in 1990 he was 22.so_random_girl
Corrected entry: In this episode The One with Joey's Fridge, Rachel's hair is just a few inches past her shoulders and in the very next episode, The One with Mac and C. H. E. E. S. E. Rachel's hair has magically grown down to her waist. No one else's hair has changed, and no mention of it in these episodes either. I guess they were just hoping no one would notice it.