The post about vacations below reminded me of a side trip I took with my family to Mammoth Cave a couple of years ago. It was late in the day and one of the last tours. The group was small, so you could quickly categorized the suspects.
There was the guy who had toured the Cave many times, and was quick to try and impress the rest of us with his knowledge, even to the point of pointing out items past tour guides had mentioned but the current one left out. I tried to stay away from this blowhard.
There was the middle aged lady with the B-52 hairdo that asked inane questions. She was harmless and seeking attention. She was only mildly annoying and the guide handled her well.
There was the rest of us, ranging from interested to bored. We asked few questions and were along only for the experience.
Finally there was THAT guy. The dumb one. He was always trying to get off the trail, go down unmarked branches, falling behind, moving ahead. He was trying to be the class clown, but really was not funny. We had to wait while he took pictures of the dumbest things like the rocks on the floor or light fixtures. A real pain in the ass. Even my kids were fed up with him inside of 10 minutes.
The highlight was when we were in the deepest part of the cave. The guide turns out the lights to demonstrate what total darkness is like. Usually, the tour is very quiet at this part because impenetrable darkness makes most people uncomfortable. Not dumbass -- as soon as he realized how dark no light can be, he was heard to exclaim "Man, I got to get a pitcher [sic] of this!". The guide tried to tell him that one, the picture will not come out, and two, he should remain still and not move. He argued that no one will believe how dark it is and he has "Jest gotta get a pitcher of this". She said again that the picture will not come out. He argued that it would; he had an automatic flash. She said the picture would look like the lighted cave. He insisted that was crazy: the lights were off. She finally asked him to hold off and she quickly turned the lights back on. He pouted the rest of the tour because she would not let him take a picture of the blackness.
Like I said, some people are just to stupid to live.