Several years ago, an old guy from outside one of the small towns in upper Maine (the tree company region, where some of the towns just have numbers instead of names) showed up at the local hardware store on a Saturday and talked to the clerk about buying a new chain saw. It was autumn, and he said he needed to get his winter's supply of wood cut up and the old saw wasn't getting it done. So the clerk showed him a couple, he picked one and paid for it, and headed back into the woods.
Next Saturday the old man was back, with the chain saw, and looking just beat to death. The same clerk waited on him, and the old man complained that the new saw was worse than his old one. He said he worked as hard as he could for the entire week and was only able to cut 8 chords of wood. The clerk was surprised, because it was one of their most popular brands and models, but he said, "Well, let's take it out back to the wood pile and I'll see if we can figure out what's wrong with it."
So out they went. The clerk checked the gas and the chain oil -- both were full. So he set the choke, yanked on the rope, and fired up the saw. Just as he was about to try cutting into a big log the old man tapped him on the shoulder and yelled, "What's that noise?"