Barney: Fine! The reason I'm upset about Marshall leaving GNB is... is...
Robin: Hey. [holds Barney's hand]
Barney: ...the meatball sub.
Robin: Huh?
Barney: It all started months ago in the GNB commissary. It was Meatball Sub Day. [v.o.] Oh, how I used to love Meatball Sub Day. And then, the most humiliating moment of my life.
Marshall: Hey, buddy, I think you got a tiny little bit of marinara sauce on your tie there. [chuckles]
Barney: [v.o.] I plotted my revenge for weeks. But nothing seemed right. Then it hit me. The answer was
so elegant and simple. An exploding meatball sub. For months, I experimented. More... marinara sauce. Finally, the sub was perfected. The plan was in place. The snare was baited. And then.. he quit, Robin, he quit! It's Meatball Sub Day today, which is why I wanted Marshall to come over and have lunch. But no. All that work wasted. [quiet sobs] You want to make God laugh, tell him your plans, right?

[ten years later, the gang join Barney in his apartment as he looks to be on his death bed:]
Robin: You're too young. This isn't fair.
Marshall: We're not going anywhere, buddy. We're gonna stay here right till the end.
Barney: [weakly] Thank you, Marshall. [coughs weakly] Marshall, can I ask one final favor, my friend?
Marshall: Yes, of course, of course. Anything.
Barney: Eat this meatball sub.
Marshall: Wh- Where'd you get a meatball...
Barney: I don't have much time!
Marshall: Okay, yes, yes, of course. Of course. Does this have some sort of special meaning?
[The meatball sub explodes and covers Marshall's face in marinara sauce]
Barney: [guffawing] I'm not sick, you idiots! I've racked up $30,000 of uninsured medical bills for symptoms I don't even have. Totally worth it! You should see the look on your face. Oh, wait, you can't 'cause it's covered in marinara sauce! [guffawing]
Ted: Uh, Barney, you got a little marinara on your pajamas.

Future Ted: [v.o.] Now around this time, Marshall had truly come to hate his job. He hated the paperwork. He hated the coffee. He hated the dirty jokes. He hated everything.
Marshall: I have to quit.
Barney: Quit GNB?! Why?
Marshall: I need to do better things with my life, okay? There's- There's an opening for an environmental lawyer at the National Resources Defense Council. Sure, it pays less, but I'd be saving the oceans, saving endangered species...
Barney: Saving chicken bones and an old boot to make hobo soup? Marshall, you can't pay your mortgage with Hacky Sacks and good vibes.