One day, three friends go hunting. Only one is very good, so the second two plan to watch him and learn from what he does.
They arrive at the hunting cabin, and get all set up. The next day, the first hunter goes out. He returns with a big deer. The second two guys ask him how he did that. They can't believe how big the deer is.
"It was easy. Found the tracks, followed the tracks, BAM! Shot the deer."
The next day, the second hunter goes out, and comes back with an even bigger deer. The third guy's eyes bug out when he sees it, and he asks him how he did it.
"Same thing the first guy did. Found the tracks, followed the tracks, BAM! Shot the deer."
So on the third day, the last guy goes out to hunt. He doesn't come back for a very long time. When he staggers into the cabin, rifle gone, all beat up and bruised, with only one boot, the other two are very surprised.
They ask him what happened.
"Well, I found the tracks, followed the tracks and BAM! Got run over by a train."