When asking someone out, do you usually just jump in and start telling them what a great date you are without any clue as to what they might be looking for or what they might want? How's that working for you?
As a peruser of many cover letters/emails accompanying resumes, I'm a bit taken aback by the number of job seekers who devote their entire covers to what THEY are looking for, how talented THEY are and why THEY deserve an interview for the job opening I posted without once referring it back to anything I asked for in my job posting.
Yipes, people, don't I deserve dinner before bed? What happened to old fashioned wooing? When I have something you want, wouldn't it make more sense for you to show that you value what I have instead of indicating in your cover letter that you wouldn't mind "hitting that."
When a cover letter clearly indicates the letter is all about the job seeker, it's a real turn-off and I move quickly on to the next applicant who treats me better. They tell me I work for a great company, they want to be part of my team, they have skills that could be valuable to me based on what I posted, etc. It's romance versus sex so if you want the best chance of staying in the game, write a love letter to the employer and forego the "I want your sex" missive. It may seem great in a song but doesn't play well in the work place. If you can't write a cover that's focused on what the employer wants and not about yourself, then you are truly better off without one. All a bad cover does for you is overshadow your resume.