Coda wrote:Also: Do everything you're told to do at least once, even if it's an obviously bad idea. (Save your game first, of course.) There are a number of achievements and funny reactions you can get that way.
I know exactly what you mean, and these moments are hilarious. Or poignant. Or both.
Some things I loved best, listed in non-spoiler manner (If you haven't played it, you won't know what I mean)

The 'I Am Different' philosopher.

Katheryn's Flux Capacitor

The James T Kirk Maneuver

The Turret Symphonic Orchestra Opera House

Wheatly peeking.

The Sistine Concrete
Moonlight 
Chell's science project

Caroline Was, and Is

Sixty Dollar Seventies

The Picture Of Dorian Johnson

Combatator Vitrified

The Not Hermit Crabs

"Yes sir, right away Mr. Johnson!"

The UP Upper Peninsula Pioneer News

Being Number Two

Flinging Into the Wheatly Screen

Logo Historico

"We should have been researching A.I. thirty years ago!"

Gel. Just Gel. Oh god the Gel. Whiteout.

Cosmic Ray 'Spalation'

"Pack your box, you're fired!"

"You can get another wad of cash into your bindle"

"This body is so huge! Ah-Hah-Hah-HAH!!!!"

The open door heart room

4000 m

1.5 volts

"Then just do it for her, I don't care, that's an order."

"I love Space!"

Holmes and Moriarty

"You came back? I wasn't expecting that..."