I have three form rejections. The one I use most often says simply not for me, I don't have a lock on the market so query other agents.
The second is a bit more terse. I use it for queries that are slapdash, noodle against the wall, what the hell, I'll just wing it. In other words, the PERSON is someone I don't want to work with even if the book sounds sort of interesting (and they hardly ever do.)
And then I have "No, thank you."
And thank you is there ONLY because my finishing school teacher has a hatpin she can and does wield from the afterlife.
So, what gets a plain no?
For starters, sexual shenanigan memoirs/thinly disguised memoirs by young men.
You think you discovered sex, and self-service, and clever pick up lines.
Oh honey, you didn't.
And the idea that anyone else is interested in what you do with your "lady tamer" makes me laugh so hard I can barely type.
Anything ANYTHING that victim-blames/shames.
She asked for it?
I don't ask for your book.
Res. Ipsa. Fucking Loquitur.
Anything that undertakes to explain religion to me.
I've got that covered thanks.
The idea that you and you alone can explain the vagaries of faith is text book delusion.
I prefer my delusions to involve Idris Elba (who is a god as we all should acknowledge.)
Anything I think is non-publishable cause it's such bad writing.
In good conscience I cannot inflict this on anyone else so I don't encourage querying widely.
On the other hand...Finnegan's Wake.
What does this mean for you?
I know you fret about your work, and worry that all those rejections and vast silences mean you can't write for spit. Unless you heard "no, thank you" you're worrying needlessly.