Let's Just Be Friends

Howard: Wrong thing to say?
Batman: Is it ever the right thing?

—Batman Beyond

A standard breakup line, commonly used in Real Life. One member of a couple suggests to the other that their romantic attachment end and they stay Better as Friends. This is usually taken badly (Unlucky Childhood Friend, "friend zone", etc.). The speaker may or may not actually wish to be friends, or indeed ever have contact with their ex again, but wants to spare the other's feelings in any case.

See Just Friends for a type of Romance Arc that the Let's Just Be Friends line can be used to end.

Examples of Let's Just Be Friends include:

Film

Starship Troopers. "Ain't it great how they want to be your friend right after they rip your guts out?"
Subverted in The Social Network:

Erica: I think we should just be friends.
Mark: I don't want friends.
Erica: I was just being polite. I have no intention of being friends with you.

Literature

Older Than Print: This actually occurs in Geoffrey Chaucer's Troilus and Criseyde (Criseyde's Dear John letter, after she has dumped him for Diomede).
In Anne of Green Gables, This is basically the line Anne Shirley hands her childhood friend Gilbert Blythe when he asks her to marry him. Twice. She comes around eventually.
Subverted with Leslie Slote and Natalie in The Winds of War/War and Remembrance. They literally are "only" friends-insofar as friendship is an "only". That is, Slote is her former lover but is beaten by a rival. He is however graceful enough to not only accept that but he remains loyal enough to devote himself to protecting her "merely" as a friend and pretty much sinks his career while doing so. As Natalie said in the miniseries, "People don't understand about us."

Live Action Television

One Seinfeld episode begins with Elaine telling Jerry how she broke up with this guy using this line- and he was actually OK with it. He wants to be friends with her until the end of the episode, and acts nice accordingly. She's puzzled by this attitude, even though as Jerry notes, their friendship started the exact same way.
Spike in Buffy the Vampire Slayer is devastated when Drusilla dumps him for a demon and says they can "still be friends". As he sobs to Willow, "How could she be so cruel? She didn't even set me on fire!"
- Saw that episode right after a bad breakup that ended with that line. Couldn't stop laughing.
Naomi tries this very line with Emily in Skins (not because she doesn't want their relationship, but because she's terrified of it); Emily's response is "we say that, don't we?". It lasts all of about twenty seconds before Emily breaks her defences down with the Armor Piercing "I'll miss you."

Music

The song "Can't We Be Friends?"
Also, Just Be Friends.

Newspaper Comics

In Dilbert, a woman says this line to the title character. Disappointed that he simply agrees, with no emotional reaction, she progressively ups the ante, first to "friends with other people. You and I would just be acquaintances," then to acquaintances that couldn't actually become friends, like "my ex-butler whom I fired for stealing stuff." When this still fails to get a reaction beyond "Okay," the woman wonders to herself what's going on, while Dilbert thinks, "Good, it seems the window of opportunity is still slightly open."

Video Games

In the intro movie of Sam and Max Hit The Road, the titular cop duo save a Mad Scientist's date from being zapped after she tells him she wants to just be friends.

Web Comics

Sluggy Freelance has Torg and Zoe's attempt at dating end with Zoe deciding they should just stick to being friends (a deranged, trained assassin Stalker with a Crush showing up to kidnap Torg had a lot to do with that, though).
In Misfile, Emily goes on a date with someone in Cape Cod. He gives her the "let's just be friends" speech at the end, saying that he noticed that she wasn't really interested in him. But then he reveals that he thinks he's gay, or at least he's fallen for his male friend. Emily tells him that she thinks she's fallen for her (currently female) friend Ash, too.
In Homestuck (or more accurately Hivebent), Feferi to Eridan after he finally spits it out upon their entrance to the Medium.
- And then Jake to Jane after she denies having feelings for him and he says that he really needs a friend right now. Unfortunately, Jane was lying.
In Sinfest, Fuschia anticipates it.
In Blaster Nation, Matt falls into this.

Western Animation

In The Curse of the Were-Rabbit, Lady Tottington asks Wallace if they can "part as friends" after Wallace fails to catch the Were-Rabbit. He's actually turning into the Were-Rabbit at that exact moment and tries to shut the door in her face. She doesn't take it very well.
In the Batman Beyond episode "Terry's Friend Dates a Robot", one of Terry's nerdy friends named Howard gets a robot girlfriend that's too devoted to him. When Howard uses this line on her, it does not go well.