The IIT professor told the student to get reference from him when applying to foreign universities. The student suspected something fishy.
Finally he asked the professor to write a reference letter for him. He promised to write and mail it.
The student was smart. He went to the post office and tipped the postman.
He gave him the letter. It was full of, “Don’t admit him. He is the worst student I have met.”
The student changed the letter to “Please admit him. He is the best I have ever met.” and mailed it.
Expected result. The professor remained wondering.