I've written many, many professional letters. Query letters are the hardest. They are hard to compose, and hard to hone, and hard to get just right. (Is there a perfect query letter?)
There may not be a perfect query letter - but we know that there are lots of imperfect ones.
Like the one I wrote stating...
"I'd like to send my novel for possible repersentation..."
Repersentation? I saw that after I hit the 'send' button, of course.
There are worse mistakes. Over at Miss Snark's blog a writer admitted to mispelling his first name. He said he'd carefully gone over the whole letter a hundred times....and mispelled his first name. (Sincerely yours, Boob)
Once I sent off a query and realized I hadn't put the title of the book anywhere, and another time I cheerfully wrote "Thank you for your kid attention."
Another person (again from Miss Snark's blog) wrote as his opening line: "I am sure you are very busty but hope you will..."
Or this one I sent off just recently: "It was perviously published..."
I would have thought spell check would have caught that one. LOL.