Ah, the flashback clip episode. This type of episode is almost always a mixed bag. It can remind you why you like the show in the first place, as it serves as a kind of "greatest hits" album. However, it's also marking time and serving as filler because a better, original episode was unable to be written for whatever reason. This is the producers asking the audience for an extension, and giving us all the reasons why we should still love them even though they're wasting our time.
Some of the reminiscing here works, but a lot of it doesn't. Part of the reason why it doesn't is that the episode has no general theme as to what is being remembered, but instead uses a skimpy story about an attempted suicide as the excuse to take a saunter down memory lane. This ends up creating a grab bag of material, some that works, some that doesn't and a lot that just feels like filler. The montage of fantasy sequences, for example, taken out of context lose much of their power and humor. The ludicrous Scrubs fantasy sequences often work because they are hard left turns in the story and often play as a counterpoint to whatever scene they departed from. Taken all together they just seem needlessly silly. To make matters worse this sequence is set to Billy Joel's "Sometimes a Fantasy," hardly a classic Joel tune and used only because it actually SAYS "fantasy."
The same can pretty much be said for the pointless "falling down" and "dancing" sequences. While the clips that fly by do indeed fill the criteria of someone either falling down or dancing, they do little else in and of themselves. The segues into these clip montages are likewise weak and tossed off with a sense of embarrassment that an otherwise fiendishly clever show is doing such shoddy work.
Where this episode does work is when it taps into the show's more obvious strengths. The montage of "people being mean to one another" is funny because it mines solid material and crackling dialogue that has earned the show a devote audience. And any reason to see a montage of Dr. Cox's insults can't be all bad. Finally, the show gets around to the emotional punch, around the same time that a proper episode would do the same. These scenes remind us of Turk and Carla's relationship, Dr. Cox's fall from Grace, and many moments where the show does its signature acrobatics with tone and effortlessly two-steps from arch comedy to poignant emotion in mere moments. This is the stuff that Scrubs is made of, it's why we watch, and why we prefer original episodes and not dashed together clip reels.
Scrubs is aware of what they're doing here, and they make a reference to it. JD actually says he keeps replaying the bad things that happened to him in his head, like "a bad sitcom too lazy to come up with a fresh story." Scrubs is certainly not a bad sitcom, but nobody is going to talk about this episode, and they'll probably skip it when it comes to re-watching the series on DVD or in re-runs.