What a cheek! / The nerve! / Can you believe the audacity!
Expresses indignation at someone's audacity or impudence. Cara literally means face but colloquially means cheek or nerve.
—He arrived late and then complained on top of it. —What a cheek!
The nerve, asking me for help after how he treated me!
—She wants you to return the favour. —Can you believe the audacity!