A man takes his sick Chihuahua to the veterinarian, where they’re immediately taken back to an examination room.

After a short wait a labrador walks in, sniffs the Chihuahua for 10 minutes and then leaves. A few minutes go by and then a cat comes in, stares at the Chihuahua for 10 minutes and then leaves. Finally, the veterinarian enters the room. He prescribes some medicine and hands the man a bill for $250.

“This has to be a mistake,” the man begins. “I’ve only been here for 20 minutes!”

“No mistake,” says the doctor. “It’s $100 for the lab test, $100 for the cat scan and $50 for the medicine.”