How can you tell a Coastguardsman is lying? He begins a sea story with: "This happened to me, no shit."

Shelley, once a shipwrecked sailor came up on an island and found himself among a crowd of other strandees. After he was greeted and everyone went back to their normal doings, someone occasionally shouted out a number and everyone laughed.
He asked his guide why people would laugh at a number. "When we were wrecked, we had only one joke book. Each joke was numbered. After a while, we knew the jokes so well that we didn't need to hear them all over again to appreciate. In fact, it would have been annoying. We agreed that the numbers were enough for us."
The strandee thought this over and decided to give it a try. He called out "Nineteen." No one laughed.
He turned to his guide and asked "Why didn't anyone laugh?
The guide replied, "It ain't what you say but the way that you say it."