What is the difference between a comma and a period?
A comma gives you a pause, but a period gives you sleep.
Hey, listen up, buttercup. This joke is playing on the double meaning of "period." See, a period is a punctuation mark, but it can also mean like, when something ends, like your attention span when I start talking. It's funny 'cause sleep means you ain't doing nothing, just like you at your job.