An automobile runs, a program does not. (Computers run, but I’m not discussing them.) An automobile requires maintenance, a program does not. A program does not need to have its stack cleaned every 10,000 miles. Its if statements do not wear out through use. (Previously undetected errors may need to be corrected, or it might be necessary to write a new but similar program, but those are different matters.) An automobile is a piece of machinery, a program is some kind of mathematical expression.
Leslie Lamport, “How to tell a Program from an Automobile”, 1977