Passes (rejections) aren’t the worst outcome of a query or read. They’re opportunities.
Worst outcome of a query is an email bounce. A pass is an acknowledgement. A – perhaps fleeting – chance for correspondence. I made the mistake early on of taking these opportunity to ask the dumbest yet most natural question: If not this, then what are you looking for?
If not a snarky response, this question is most likely to solicit no response at all.
I finally realized there are two questions that I can ask that most execs will answer: What genre are you currently seeking? And in what budget range? The answers to these two questions are always readily available. This fact should also give you a lot of insight into what guides these people’s decisions.
With passes on actual reads I would always ask for notes. Rarely get them, but I’d always ask. When I was fortunate enough to get feedback I’d make sure to give it very careful consideration. There’s no use arguing. Or telling them you’ll do another draft. Move on with the insight and try to keep that relationship going in the future.