I'm interested in getting into Fringe, but there seems to be a pretty universal consensus that it only starts getting good in season 2. How much of season 1 do I need to watch if I want the later seasons to make sense?
Honestly, very little of Season One is needed if you go into Season Two with the following assumptions:
- The existence of the Fringe Division of the FBI is accepted by the FBI, and
- Peter and Olivia have completely valid reasons to believe Walter can basically do whatever he says he can do.
- No, you're not crazy, those bald guys are super creepy.
Season One was very much a "monster of the week" season. Much of the early episodes were spent building up Walter's credibility, and integrating Peter back into his life after many, many years of no communication. There is one major season-wide arc that I'm not sure ever got really resolved, though recent episodes are hinting that it is "coming back up".
The second half of season one starts to introduce the primary premise of the rest of the show, particularly starting with "Bad Dreams" (s01E17). If you start there, with the descriptions of Olivia's and Walter's "origin stories" that are hinted at over the last few episodes, you should be fine. The season finale, in particular, sets up basically all of the key plot elements that we discover over Season Two
Having said that, there are a lot of minor plot points in Season One that get called back to later on, especially in this most recent season. And while I do agree that the show got better as that season progressed, even the earliest episodes were pretty good, and I would recommend you watch them anyway. If nothing else, you can occupy yourself with how many different ways Walter can mis-pronounce "Astrid".
Season 1 is, as Michael Edenfield said, very much Monster-Of-The-Week, and not highly important to seasons 2 and 3.
However, at the end of Season 3/beginning of Season 4, a major shift happens, and knowing Season 1 will greatly help your comprehension. Without trying to spoil too much:
- David Robert Jones (and his plan)
- Cortexiphan (And everyone involved)
- Usage of the ZFT
- How the Observers were introduced
- The Pattern (The cause and reasons for it now seem apparent in late season 4)
- September's actions
Basically, almost all of the Monster-Of-The-Week episodes in Season 1 have been tied together into a cohesive whole. Only about 5 of the 20 episodes in Season 1, I can't immediately tie into the overarching storyline. And at this point, I'm sure I could if I re-watched those episodes.
This question was answered on io9. The suggested episodes are:
- S1E01 "Pilot"
(Introduction to the series)
- S1E04 "The Arrival"
(Introduction to the Observers)
- S1E10 "Safe"
(Introduction to David Robert Jones)
- S1E14 "Ability"
(First hint that there's more to Olivia than meets the eye)
- S1E17 "Bad Dreams"
(A bit of background of Olivia explained)
- S1E19 "The Road Not Taken"
(First glimpse at alternate universes)
- S1E20 "There's More Than One of Everything"
(Season's finale, first look at William Bell)