Stupidity

One day the barber said to customers when a boy passes in front of his barbershop, "That Tom, he's the dumbest boy in the world!! Ha ha ha.."
"Is that right?" said the customer.
Then the barber called Tom, he reached into his pocket and showed the money $ 1 and coins of 50 cents, and told Tom to choose, "Tom, you may take one of this money, it's up to you to select which one, c'mon boy, pick one!!"
Tom saw the barber's hand where there is money $ 1 and coins of 50 cents, then quickly moves his hand to take the 50 cents coin.
The Barber feel happy and proud turn to the customer and said, "See what I said earlier? Tom was the stupidest boy I ever met!! Countless times I did a test like that before and he always took a coin whose value is the smallest!! Ha ha ha, what a stupid boy!!"

After the customer finished cutting his hair, on the way
home he met Tom. Feeling curious about what he saw before, he was called Tom and asked, "Tom, I watched as the barber offers money $ 1 and coins of 50 cents, and I see you take 50 cents coin, why don't you take the money 1 $ it? Isn't worth 2 times than 50 cents coin?"
Tom said, "Because if I do that, I would not be 50 cents more each day.. The barber always wondered why I did not take the money that $ 1, so he did this every day.. If I take a $ 1 , means the game will be finished..."