[Seinfeld] you could use a little flash.

 

GEORGE: I don't like it, it's red. It's-it's too flashy. (03:21)

SUSAN: Well, you could use a little flash.

 

In this line, “you could use” is not about literal use or permission. It’s a polite, idiomatic way of giving advice or making a mild judgment.

Grammatical structure

• could + base verb

• Here, could expresses suggestion / advisability, not ability or past tense.

So:

“You could use a little flash.”

means:

“It would be good for you to have a little flash.”
“You need / would benefit from a bit of flash.”

Pragmatic meaning (what Susan is really doing)

Susan is:

• softening criticism

• teasing George

• implying that George is too plain, dull, or conservative

Using could instead of need makes it:

• less direct

• slightly ironic

• conversational rather than confrontational

Compare the force:

• You need a little flash. → blunt, judgmental

• You could use a little flash. → indirect, mildly critical, socially polite

Why “use” works here

English often uses “could use” idiomatically to mean:

• lack of something desirable

• would benefit from something

Examples:

• I could use some sleep.

• This room could use more light.

• He could use better manners.

None of these imply active “using” — they imply deficiency.

Bottom line

In this sentence:

“You could use a little flash” = “You are lacking flash, and you’d be better off with some.”

It’s a softened evaluative judgment, delivered as casual advice rather than a direct criticism.