Barber and the boy

Once upon a time in Paris there was a barber shop , it was one of the most famous barber shop in the streets of Paris , the barber shop was run by a old man . One day when a young boy was passing by his shop ,The barber loudly narrates his name and ask him to come to his shop ,the boy entered his shop when he was coming to his shop the barber told his customers that this guy is so funny and he is one of the most idiot persons on this planet ,he said "I will prove this in front of you people"! 
 The barber put 100 EUR in one hand and 20 EUR in other hand then the barber call the boy and ask him "which do you select" the boy garbed the 20 EUR from his and and went away !
when the boy left the shop the barber laughed loudly and said "did u watch i told you , this is the
dumbest guy in the world!"
later when the customers were gone he saw the same boy coming out of the ice cream parlor ,boy was very happy he was licking the ice cream there was a smile on his face  , the barber was very curious to know this fact that why he always select the less money ! the barber shouts at the boy and ask him to come to his shop again, when the boy came, he asked him that why he select the less money always!
the boy didn't see his face he was busy in licking his ice cream! by licking his ice cream he replied
"the day i select the 100 EUR the game is over "