Chaplin was experiencing a tense life in the movie. He had to work fast in order to catch up the speed of the machine. That gave him a great pressure that he couldn't help stop himself working. He addicted inevitably to repeat his working gesture, screwing, while seeing anything resembling a screw. Chaplin playing a joke on this was an irony to the new technology which gave rise to mental problems to people. That's why he was messing up in the factory eventually.
Such problem extends to the social aspect. Disputes raised among Chaplin and people in his working environment, including not only the fellows of Chaplin, but also innocent passer-by happening to rush into Chaplin. Machines involving in lives seem to be obstacles within interpersonal relationship. Much coordination has to be drawn to get along with one another.
Chaplin told the problem in the sense of humour. The reality is our lives are affected by new technology in a subtle way. I would like to share that I always flow into a rage when I can't manipulate the computer properly. Digital environment forms a rushing lifestyle. People get used to it and are prone to be impulsive and sensitive to efficiency. And I am one of the victims.