A man went into a pet shot and admired three identical parrots. Outside of their enclosure was a sign which read "see clerk for prices."

He called the nearest employee and asked, "am I correct that these birds have different prices?" The clerk nodded. "Excuse me, but they are identical. Why wouldn't they all be the same price?"

"Ah, you see the bird on the left costs $500 because he knows Microsoft Office."

Dumbfounded, the customer responded, "you're kidding."

"Not at all, sir. The one on the right knows LAN, so he goes for $2,500. The one in the middle goes for $15,000."

The man staggered at hearing the prices. "So why does he go for $15,000? What does he do?"

The clerk gave him a grin and replied, "Well sir, so far I haven't been able to figure out WHAT he does, but the other two call him 'BOSS.'"