In response to an advertisement for a territory salesman my company received a resume and cover letter submitted by one of our competitor's employees. The first paragraph of his cover letter was written as follows:
I am currently employed as a store manager at XYZ Company. They have three stores with their main office located in Milwaukee. I am employed at their Madison location. XYZ Company is managed in such a way that I am continuously working in a reactive mode.
The last sentence automatically disqualified this candidate from further consideration. Our owners perceived two things from this sentence.
1. Our competitors have the same problems we do.
2. This candidate most likely has a bad attitude, especially towards the management of XYZ Company.
The purpose of a cover letter is to explain why an employer should want to hire you. The above candidate had been promoted from salesman to store manager at his present company. He would have faired much better if he had written what a great salesman he had been, how he misses sales and would love to have the opportunity to sell for our company. He currently commutes from Milwaukee to Madison each day. By stating he would prefer a position with a shorter commute, although not a reason we should hire him, would have at least not eliminated him.
For an example of a great cover letter read Ask a Manager’s post "What Does a Good Cover Letter Look Like".