Yo afish
More than most years, this season I've noticed that trouts often outright miss the escaping bug. This has happened not just with caddis, which can be pretty speedy on the emergence, but also Mayflies, big and small. So it makes sense that some of the rejections I get are just plain misses. When I think that is happening, I immediately recast my imitation and often the frustrated trout grabs on it. In the cases where I think the trout did reject my fly, I might pause before recasting, or might present it again from a slightly different position in order to alter the microdrag. Or I might change the fly, sometimes to another of the same pattern (on very picky streams like the Beaverkill or Lil Lehi) - and with the retying and all, there is an automatic time delay with the mechanics of the changeout.