An accountant goes into a pet shop to buy a parrot.
The shop owner shows him three identical parrots on a perch and says, "The parrot on the left costs $500." "Why does that parrot cost so much?" asks the accountant.
"Well," replies the owner, "it knows how to do complex audits." "How much does the middle parrot cost?" asks the accountant.
"That one costs $1,000 because it can do everything the first one can do plus it knows how to prepare financial forecasts".
The startled accountant asks about the third parrot, to be told it costs $4,000.
Needless to say, this begs the question, "What can it do?" To which the owner replies "To be honest, I've never seen him do a darn thing, but the other two call him Senior Partner."