I liked Friends the first time around but I didn't avidly watch every episode.
When it popped up on Netflix I was rather blase and thought I'm not going to watch it. But earlier this week I just wanted something short, light and funny to watch and ended up watching about four episodes! I don't know whether it's coz I was too young then to appreciate it but I've found myself laughing out loud now and can really relate to what's happening to them. Maybe coz there's so many series, first time around the characters start grating after a while but right now I'm really liking them. I'm actually only really noticing Monica now and think she's fab. Phoebe also seems less annoying.
Often when you rewatch something you liked, on a second watch it's disappointing but I think Friends might be the rare one that's better on second viewing.