Any Idiots in the Classroom?

"If there are any idiots in the room, will they please stand up" said the sarcastic teacher.

After a long silence, one student rose to her feet.

"Now then young lady, why do you consider yourself an idiot?" enquired the teacher with a sneer.

"Well, actually I don't," said the student, "but I hate to see you standing up there all by yourself."