No matter how much you my dislike your boss, be civilized in your emails to him or her; otherwise, they may come back and bite you.
In Zayas v. Rockford Memorial Hospital, a 7th Circuit Court of Appeals case decided last week, an ultrasound technician alleged that her hospital employer discriminated against her under Title VII of the Civil Rights Act and the Age Discrimination in Employment Act when it fired her in April 2011. For her national origin discrimination claim, Zayas relied on largely on a racist comment made by a co-worker. The hospital argued that it terminated her because she sent her direct supervisor a series of disrespectful emails, and that she continued sending such emails despite her supervisor's repeated warnings to stop.
The emails, according to the court, gave her employer sufficient reason to terminate her, and indicated that she was fired due to her failure to meet her employer's expectations. Even though Zayas claimed her emails were not egregious enough to justify termination, they were bad enough to elicit warnings from a supervisor, and that should have put her on notice that she would be fired because of them, not as a result of discrimination.
If you feel you have a discrimination complaint, its ok to put it in writing, but do it in a professional manner. Don't give your employer an unrelated reason to send you walking.