Source: http://www.ling.upenn.edu/~beatrice/humor/ambiguous-recommendations.html#structural

Ambiguous recommendations

If you have to write a letter of recommendation for a fired employee, here are a few suggested phrases.

Lexical ambiguity
For a chronically absent employee	A man like him is hard to find.
For a dishonest employee	He's an unbelievable worker.
For a lazy employee	You would indeed be fortunate to get this person to work for you.
For the office drunk	Every hour with him was a happy hour.
Structural ambiguity
For a chronically absent employee	It seemed her career was just taking off.
For a dishonest employee	Her true ability was deceiving.
For a stupid employee	I most enthusiastically recommend this candidate with no qualifications whatsoever.
For the office drunk	He generally found him loaded with work to do.
Scope ambiguity
For an employee who is not worth further consideration as a job candidate	All in all, I cannot say enough good things about this candidate or recommend him too highly.
For an employee who is so unproductivethat the job is better left unfilled	I can assure you that no person would be better for the job.
Other
For a lazy employee	He could not care less about the number of hours he has to put in.
For an employee who is not worthfurther consideration as a job candidate	I would urge you to waste no time in making this candidate an offer of employment.
For a stupid employee	There is nothing you can teach a man like him.