[s2e21] Paradigms Of Human Memory -

The "flashbacks" include increasingly absurd and high-stakes scenarios that never appeared in prior episodes:

The episode culminates in a meta-parody of Jeff’s typical inspirational speeches, which is edited together from fragments of various "unseen" speeches he gave throughout the year. Production Facts "Community" Paradigms of Human Memory (TV Episode 2011)

The episode parodies "shipping" videos with a montage of "stolen glances" between Jeff and Annie set to the song "Gravity" by Sara Bareilles—a direct reference to actual fan-made videos.

A sequence suggesting the group was briefly institutionalized.

A montage of Dean Pelton entering the study room in increasingly elaborate outfits, such as a Caesar salad or a "Gone with the Windows" ensemble. Narrative Revelations & Meta-Commentary