Why do some people insist on sharing their personal sexual behavior with everyone else?

Wouldnt it be just as rude and objectionable to show everyone at the dinner table a small sample of my stool? Or color photos of my girfriends vagina, clippings of my pubic hair, or rolled up balls of snot? Is anyone really interested in the unsolicited description of bedroom behavior of others or are folks starting to grow weary of these demented screams for attention?