I've had a couple of good PA announcements. First one was landing in Seattle. We came down very hard, and the cabin PA announcement was along the lines of: "As you will have realised we've arrived in Seattle...". The Captain then came on (BA "Biggles" type) and said: "Oh sorry about the landing ladies and gents, playful bit of wind shear". Yeah, right!
Second one was just prior to a very VERY bumpy approach into Dublin. The Captain, to his credit, warned us that it was going to be very bumpy, as well as telling us not to be alarmed if we started climbing again in case it was just too windy to land. However, he spoiled it for the more nervous amongst us by saying that: "some of the planes in front haven't made it."