I went to the doctor and told him I had a terrible addiction to checking my watch.

This joke tickles our funny bone through clever wordplay, specifically a pun. The phrase "it's just a matter of time" is a common idiom meaning that something will inevitably happen at some point in the future. However, in the context of a patient obsessed with checking their watch, the doctor's punchline takes on a literal meaning, referring directly to the patient's preoccupation with "time" itself. It's a delightful linguistic twist that catches us off guard.

The humor is enhanced by the relatable, albeit exaggerated, scenario of being overly concerned with the clock. In our fast-paced world, many of us feel a constant pressure to keep track of schedules and deadlines, making the idea of an "addiction" to checking one's watch a humorous amplification of a common modern anxiety. Instead of a serious medical diagnosis, the doctor offers a witty, unexpected quip that plays on the very nature of the patient's complaint, providing a lighthearted take on our relationship with time.