If a computer knows what a person is trying to accomplish, it's not the computer's job to actually do what the person was asking to do. It's the computer's job to tell them the correct way to do what they're obviously trying to do.

how-to-be-an-asshole.py

def setquit():
    """Define new builtins 'quit' and 'exit'.

    These are objects which make the interpreter exit when called.
    The repr of each object contains a hint at how it works.

    """
    if os.sep == ':':
        eof = 'Cmd-Q'
    elif os.sep == '\\':
        eof = 'Ctrl-Z plus Return'
    else:
        eof = 'Ctrl-D (i.e. EOF)'

    class Quitter(object):
        def __init__(self, name):
            self.name = name
        def __repr__(self):
            return 'Use %s() or %s to exit' % (self.name, eof)
        def __call__(self, code=None):
            # Shells like IDLE catch the SystemExit, but listen when their
            # stdin wrapper is closed.
            try:
                sys.stdin.close()
            except:
                pass
            raise SystemExit(code)
    __builtin__.quit = Quitter('quit')
    __builtin__.exit = Quitter('exit')