A man arrives at the repair shop to pick-up his watch.
Clerk: "I haven't finished repairing it yet. just give me a few more minutes.
Man: "Sure, no problem."
The man goes and stands right next to the clerk, who notices him but continues working. After a while, he can't take it anymore.
Clerk: "Why are you sticking so close to me?"
Man: "I'm only doing what the sign outside your door says."
Clerk: "And what is that, may I ask?"
Man: "It says, 'Watch Repairs.'"
Teacher: "What is an OS? And give me an example."
Student: "An OS is a word which can be used instead of saying 'Oh Yes'. For example, do you like ice cream? You can reply, ‘Oh, yes' or 'OS.'
Teacher: "You may sit down now."