Are you kidding me?
American SlangDefinition
A rhetorical exclamation expressing disbelief, surprise, or annoyance at something that seems absurd or unacceptable.
Examples
"When the cashier rang up $18 for a small salad, I whispered, 'Are you kidding me?'"
"Hearing that the meeting was moved to 6 a.m. on Saturday, she sighed, 'Are you kidding me?'"
"After he claimed he forgot his homework for the third time this week, the teacher muttered, 'Are you kidding me?'"