Thoughts about how the seasons rank now that the show has ended? For me it's something like this:
1. Season 1 (tie): Not every episode hits it out of the park, but this is the season that hooked me and the one that I still rewatch the most. I also consider it the high point musically. It's crazy to me how many great songs were packed into just the first couple of episodes: "West Covina," "Sexy Getting Ready Song," "Feeling Kinda Naughty," "I Have Friends," "Settle for Me," just to name a few. It also helps that this season was heaviest on Josh and Greg, both of whom I far preferred to Nathaniel.
1. Season 2 (tie): I feel like this season might have been the tightest narratively. I think of it as three arcs: the development and quick disintegration of Rebecca's love triangle; the rise of the girl group; and the manic Rebecca/Josh relationship, with its dramatic implosion on their wedding day. Lots of classic songs, particularly when Greg was still around: "Tapped that Ass," "Math of Love Triangles," "Ping Pong Girl," "Shit Show," Friendtopia," "We'll Never Have Problems Again," etc.
3. Season 3: I have a weird relationship with Season 3 because there was a stretch of episodes (4-6) that are among my favorite in the show's entire run (with Episode 4 - the Swimfan ep - remaining my absolute favorite). I think the show really was at its best - funny, dark, emotional - when exploring Rebecca's mental health issues. "A Diagnosis" is the song that probably packs the biggest emotional punch for me. Honestly, the entire first half of the season is pretty good (I put on some old eps recently and even numbers that I thought of as forgettable - e.g., "Head in the Clouds" - are fairly enjoyable.) But then it all went to crap. I thought there was way too much time spent on Rebecca/Nathaniel, and I wasn't a fan of the donor egg/surrogacy plots. Plus, the songs in the back half just weren't memorable to me.
4. Season 4: I really hope this improves upon rewatch, but Season 4 felt like the show spinning its wheels. There were no real arcs, save for the drawn out, repetitive love quadrangle. There were some highlights here and there, but it felt like there were always three bad episodes followed by one good one. Songs were much worse (and seemingly less frequent) than previous seasons, although I do love "Don't Be a Lawyer," "Love's Not a Game," "The Darkness," and a couple of others.