Dear Miss Snark,
I've been reading your blog for a while so I do know that if I assume that my writing doesn't suck then 1) I must follow agents' directions, 2) query widely and 3) not take rejections personally. I understand that publishing is a business so could you give me the business reasons why an agent would reject what is an "engaging novel" with "believable characters" and a "relatable plot". (These quotes are from my various rejections letters.) Isn't that what sells these days?
You cannot parse out the reason for no or you will go crazy.
It's a one way ticket to the loony bin, not to Clooney &Gin and that's not where you want to be.