An airliner is flying accross country, when the pilot comes on the PA to announce, "we have some bad news. One of the engines just failed and as a result, we will be delayed by 30 minutes."
A bit later, the pilot returns, "we have some more bad news. Another engine just failed, and we will be delayed an additional hour."
Another bit later, "Sorry folks, more bad news. A third engine just failed, and so, since we will be running only on the one remaining engine, the flight will be delayed by another two hours."
At this point, a disgruntled passenger turns to his neighbor and says, "I sure hope that last engine keeps working or else we'll be up here all night!"