These days, every time a long-running TV series -- like "Mad Men," for example! -- announces that it's shutting down for good, it seems like the Internet goes into overdrive. Fans obsess over every little detail of the final season and reminisce about all the show's past triumphs and wrongdoings. Critics are compelled to scrutinize the closing episode even if they don't regularly cover the series. Even people who've never watched before attempt to pick up the show mid-stream so they can figure out what everyone's going on about.

But why? Why are we so compelled to embrace television endings? Where are all these FEELINGS coming from?

In the wake of last weekend's "Mad Men" finale, we spoke to Jason Mittell, a TV critic and media studies professor at Middlebury College, about this finale-loving phenomenon. His most recent book, "Complex TV: The Poetics of Contemporary Television Storytelling" has a chapter dealing on the very subject of television endings -- which, contrary to what you might expect, didn't suddenly become popular with the advent of cable networks like AMC.

"It is a longstanding tradition that on a big show, a television finale will be the most watched, most anticipated episode -- when a series is actually given a finale," Mittell told us over the phone. "The vast majority of series don't have finales, they just end. Sometimes they're cancelled midseason. More often for a show that's been on a few years, they'll just say at the end of the season, 'Okay, we're done!' It's pretty rare throughout American television history for a series to actually get a final send-off in the form of a finale.

So when a show gets to announce before the beginning of a season when its last episode will be, the result always translates to more attention -- which, historically, also means higher ratings. The "M.A.S.H." finale, for example, is still the highest-rated fictional TV episode of all time with an estimated 125 million viewers, closely followed by the "Roots" miniseries finale (99 million viewers), The "Cheers" finale (93.5 million) and the "Who Shot J.R.?" episode of "Dallas" (88.6 million).

"The 'M.A.S.H.' finale, the 'Cheers' finale, 'Seinfeld,' "Friends," these were all big events," Mittell noted. "The fact that [these episodes] are most-watched suggests that many many people, millions of people, who watched the finale were not regular watchers of the series. They were maybe erratic watchers... my guess is most ['M.A.S.H.' finale viewers] had seen a few episodes at least, but very few of those people has been regular weekly viewers of the show, even though it was certainly a hit show."

So why does it FEEL like we've become so much more obsessed with finales, even if we've traditionally always been tuning in? Because television as a medium has moved towards telling much longer, more drawn out stories that can't be resolved in a single episode, which means the collective consciousness of pop culture feels much more invested in these stories' conclusions. Like, really invested.

Okay, maybe not THAT invested. But still.

"Serial television is one of the most broadly important sites of shared popular culture. There are a lot of shows that seem to tap into a much more broad audience than a lot of other media, which tend to be a little bit more niche-based," Mittell said. "What we're seeing now is, at least among some people, serial TV shows become the water cooler conversation -- that you can assume, in an office or at school or whatever, that other people you'll encounter will be invested in it."

"It's also part of the drive of FOMO, 'Fear of Missing Out.' There's a sense of, 'What am I missing?' So if there's a show that everyone is talking about, you'll be like, 'Oh, I need to see what all the hype is about,'" he added.

Of course, as a longtime critical television darling, "Mad Men" has always faced much more scrutiny then its ratings might lead one to believe it actually deserves. The show's finale got only 3.3 million viewers on Sunday night, which is much lower than the average episode of "Law and Order SVU" in a given week (the 15th season had an average of 8.18 viewers per episode).

"Mad Men was never a ratings sensation. It's had a very small audience," Mittell pointed out, noting that even AMC's other recently ended hit show "Breaking Bad" had a higher finale viewership at 10.3 million. "But if you go on Twitter or read any online culture magazine or site, the perception is that "Mad Men" ending is the most important thing that's happening in popular culture right now."

So, don't expect the "Mad Man" love to fade for a while -- at least, until the next big series finale grabs all of our attention away.