We've been having toilet troubles for a few months, one just didn't flush with enough vigor.  I tried snakes, a toilet auger, fancy plungers, all to no avail.  None of the other drains or the other toilet had any problems, so it probably wasn't the sewer system.  So I finally called the pros out, a very nice plumber from Roto Rooter. He tried everything, and felt it was probably one of the "ports" that push water towards the drain wasn't developing enough pressure, probably due to calcium deposits. We worked on for a while with some wire, but couldn't get it working any better.  We discussed replacement toilets, and I was about to go out and get a replacement Kohler. Remembering how difficult getting the rusty mounting bolts off, I asked him to pull the toilet, since I hadn't used up my hour minimum.

A few minutes later, I heard him say, "holy cow! There's nothing wrong with your toilet."