The announcement varies in its degree of annoying-ness.

Some flight attendants keep the announcement short and sweet, whereas others seem to repeat it, or drag it out..."once again, ladies and gentlemen, this is a very limited time offer", "ladies and gentlemen, just to reiterate, upon completion, you will be eligible for..."

I think I've had some flights where the announcement lasted 10 or more minutes...I've learned to tune it out, or turn up my iPod.

I get it though, the FAs get $5 (?) for every application that is completed.