"George Adams" wrote in
oups.com:

The idea is to get the fly in front of the target fish when he
is ready to take, and the more casts, the better your chances,
providing you don't spook the fish.

I usually don't get that many chances at a rising trout. The guy was
whipping the fly off audibly and it did not seem to matter. Those fish
seem to key in on the hatch, but on other rivers, a bad drift could
mean the last you'll ever see of that fish. A nice lady commented to me
at the SS last Sunday, "You could drop a piano in here and it wouldn't
bother the fish."