LogFAQs > #975692629

And Selphie was always off, even as a child, delighting in the death and destruction:

Irvine: "Sefie, whacha playin!?"
Selphie: WAR!

And in the game's final acts, Selphie goes full mask off and just commandeers a spaceship to go plow face first into the Lunatic Pandora. Party has accepted their fate:

https://www.youtube.com/watch?v=AEK3hmYkg44

Quistis: "Ahh... Excuse me, we're flying?
Zell: "I hope this ain't the case but, I can picture Selphie in the pilot seat, and..."
Quistis: "...Selphie screaming, 'Whoo-hoo, we're flying!' (And standing next to her, a very excited Irvine...)
[The three head up to the cockpit.]
Selphie: "Whoo-hoo! We're flying!"
Irvine: "Selphie's just amazing!"
Squall: "You sure you can fly this?"
Selphie: "It just kinda took off! I don't know. It's pretty easy. I think it'll be fine. But there's no guarantee it won't crash!"

Quistis: "Are the machine guns and main cannon ready?"
Selphie: "Rrready! Let's just fire like crazy and make a big hole, BOOM!"
[FMV. The Ragnarok fires at the outer shield of the structure but is repelled.]
Irvine: "Shields!"
Selphie: "WHOO-HOOO!!!"
[Selphie rocks back and forth in the pilot seat]

End of game Selphie gives zero fucks too:

[They finally defeat Ultimecia once and for all. There is only a white room now, and everyone is running around in it except Squall.]
Irvine: "Is it over? Let's go! Let's go back to our time!"
Selphie: Shut up! Just calm down and think where we have to go."

And of course, the escapism of the train song:

Selphie: "Train Train Take Us Away. Take Us Away Far Away. To the Future We Will Go. Where It Leads No One Knows."

So there you go. Selphie the Unhinged. Barely keeping it contained for the entirety of the game until she finally gets to unleash it all at the end. I love this little psycho, and I really do think she's underrated because people don't look past the bubblepop.