I had a bit of a scare last week. Servicemen from my oil company came to perform maintenance on my furnace. They had to leave temporarily to get some spare parts. Soon afterward, I tried to go to the basement to get something from the freezer, only to discover that my elevator wouldn't work. I called the elevator service company to report the problem and the dispatcher said she'd contact a service team who would return my call. The oilmen returned a few minutes later. It occurred to me then that they might have thrown the wrong breaker switch when they were trying to shut off power to the furnace. One of them went back to the breaker panel and discovered their error. I then received a response from the elevator company's repair team, who said they could be at my house early that afternoon. I told them what the oilmen had done and apologized for wasting their time. 
"The world is my country; all of humanity are my brethren; and to do good deeds is my religion." (Thomas Paine)
