A doctor has some trouble with the sink, on a public holiday. He calls the local plumber, only to be told it's his day off ...
"But I get called out on my days off, too!" says the doctor, somewhat exasperated, and the plumber relents.
The plumber arrives, and glances over the sink, looking preoccupied. He mumbles something about golf, then hands the doctor a couple of aspirin and walks out, saying,
"Put these in. If it doesn't clear up in 24 hours, come and see me tomorrow."