Thomas A. Edison

At the Grand Trunk Railroad, 14-year-old Edison saved 3-year-old Jimmie MacKenzie from a runaway boxcar. Jimmie's father, station agent J.U. MacKenzie was so grateful that he taught Edison how to operate the telegraph machine.
Later, Edison became a telegraph operator for Western Union. He requested the night shift so he could have more time for his experiments. One day he accidentally spilled sulphuric acid while experimenting on a battery. The acid ran between the floorboards and onto his boss' desk below. Needless to say, Edison was fired the next morning.