I was once on a LH 747 out of DFW and there was a severe storm with icing. DFW does not have a huge capacity for de-icing due to the rarity of the event, so there was a significant delay. The Captain's announcements were entertaining, informative, and useful and seemed to be appreciated, judging by the applause he received, by the entire aircraft, including the business class cabin where I was seated.
Bealzebub has made some very valid points, and whilst I appreciate that there are few things more critical than the safety of an aircraft and its passengers, there can still be a place for humour.