First, let me say that I love, love, love Shifter's post. The only reason I (a girl, in case the name didn't quite have you convinced) don't quote movies in every single conversation is because some people might not get some of the references. But I definitely believe film quotes have a rightful place in nearly every conversation. Part of it is as simple as "Why reinvent the wheel--someone else has already summarized our situation with the perfect turn of phrase." But it's more than that--as Shifter so deftly pointed out, it's a shorthand that gives you the context, the tone, the feeling behind an utterance. "Office Space" is the perfect example, conveying at a stroke, "We all know this is unpleasant and quite possibly the stupidest thing we'll do today, but what can I tell you, people, we work in corporate America." With the right person or group, you can get there even faster with just one Lumbergh-drawled "Yeah."
Popular in most of the offices I've worked in is the phrase (although not exactly a quote) "crossing the streams bad." Ghostbusters is more useful in IT than you might at first suspect.
And it's not just movies. I'd throw television in there, too. Consider, if you will, the value of the following phrases:
"No soup for you!"
"Danger, Will Robinson, Danger!"
The Twilight Zone Theme
Seriously, if you get through the day without these, I don't want to know how you do it.
I know you can do it, but you're missing out on something valuable. Yeah, Shifter can tell his team the whole song and dance about how corporate America sucks but he cares about them as people and doesn't want to be a jerk. All of this can be (and is) true. He can even (and I truly believe this) make it sound like the St. Crispin's Day speech from "Henry V" every single time. But you know what? The St. Crispin's Day speech was so friggin' awesome that hundreds of years later, the Marines were still drawing on it for their recruiting ads (sure, they cut it down a lot, but let me tell you that "The Few, The Proud, The Marines" is pretty much the St. Crispin's Day speech magnificently, brilliantly, and effectively summarized).
I'm not exactly saying the "Office Space" is the "Henry V" of our time--corporate stupidity may well turn out to be as enduring as war, but war has a way better claim on being hell than life in a cubicle. But the argument, if one were to make it, is not so far off the mark. Shakespeare was a popular entertainer who deftly summarized huge swaths of the human experience in ways that were meaningful to his audience--and if you compare "Office Space" to a Shakespeare comedy, you're going to find more commonalities than you might think.
By using a common reference from pop culture to get your message across, you say more than, "I don't want to be a jerk." You say, "you and I are the same--we share a common experience and a common culture, and you and I are united against [in this case] our corporate overlords, even though right now we're gonna do what they asked us to." And that's something you can't do with Shakespeare, because (and this is not a value judgment in any way--I love Shakespeare, but I also love current pop culture) it's not a common experience today. To get your message across and to really capitalize on a reference of any kind, the reference has to come from a cultural form that carries currency with the humans you interact with--today that's movies and television far more than any other type of shorthand.
The other great thing you can do with a cultural reference is make it as broad or as specific as you like. You can make a really big one that's widely recognized, or you can keep it to something that only your little special group will understand. It's incredibly useful, and something that humans have done for centuries with words and symbols.
It's definitely possible to do all of this without quoting a movie or a TV show--but that's something that only very, very special people in a special situation can do with original rhetoric. We don't all get to be "Ask not what your country can do for you." We just don't. But we can all toss out a reference to our "flair" and get through our corporate servitude with just a little more good cheer. And that's none to shabby, if you ask me.