The experience of humor is similar to the “ah-ha” moment of two things coming together. For humor, two things have to come together to produce the experience of laughter. Normal and abnormal; these things reconciled in a moment, and usually it’s a normal situation violated in some way that we can tolerate. You have to have something normal that becomes abnormal, or something that looks abnormal and then become normal.
So, normal: there’s a guy on the phone, saying “No, Thursday’s out. How about never - is never good for you?” Everything is normal - the office, the syntax of politeness - and yet the message is rude. We have a violation where we have a normal situation.