Wiktionary
all work and no play makes jack a dull boy
prov. 1 Too much focus on one's career is often viewed unfavorably. 2 Too much hard work and not enough leisure time can be unhealthy.
Wikipedia
All work and no play makes Jack a dull boy
All work and no play makes Jack a dull boy is a proverb. It means that without time off from work, a person becomes both bored and boring.
Usage examples of "all work and no play makes jack a dull boy".
Haven't you ever heard that line about 'all work and no play makes Jack a dull boy?