Cover Letters... or How to Dupe Employers Into Hiring You

Writing cover letters is a noble art. It's a chance to let your creativity rise to the challenge of creating a whole new, employable persona - which probably doesn't even resemble the 'real' you.
You're expected to cram who you are, what skills you have and what you can offer into one side of A4.  Basically, you have to market yourself as an employable product.

Looks about right?

Personally, I have trouble writing cover letters. I get bogged down by the job descriptions, and trying to figure out what I'm expected to say. I always end up sounding pretentious - at least I think so. It's always something along the lines of:

"You must hire me. I am obviously the best candidate. I have all these skills *insert skills here*. You clearly stated in your job description that you need people with *insert skills here*, which, as I mentioned previously, I have.
By the way, did I mention I have all these skills? Because I do. So you should hire me. I am the best candidate."

It sounds so stilted and impersonal. If I were called in for an interview, they would barely recognise me based on that letter. I'm not that conceited individual, inadvertently snubbing all other candidates applying for the position.
But everyone does it. We all have to write cover letters at some point in our lives. It's almost a sucking-up competition. You write like 20 versions, sending them out to different employers telling each of them how much you would love to work for them, because it's the only place you can envision yourself working at.
And this, just like your new cover letter alter-ego, is all lies!
But they want us to lie, why else were CVs invented? Nobody tells the truth in CVs or cover letters. If we did, most of us wouldn't even be working. Employers must love being sucked-up to, because we all blatantly do it and so far, nobody has complained.
Growing up is a b****