The shop owner points to three identical-looking parrots on a perch and says, "The parrot on the left costs $500 dollars."

"Why does that parrot cost so much?" asks the man. The owner says "Well the parrot knows how to use a computer."

The man then asks about the next parrot and learns that it costs $1,000 dollars because it can do everything the first parrot can do plus it knows how to use the UNIX operating system.

The man then asks about the third parrot, only to be told that it costs $2,000 dollars.

"What can it do better than the others?" asks the man.

The owner replies, "To be honest, I've never seen it do anything, but the other two call him boss."