R’ Nachman of Tulshin was asked: ‘Why do the Sages say that the minds of the learned (talmide chachamim) become more settled the older they become, and the minds of the ignorant become sillier and sillier with advancing age?’
‘Once, he answered, ‘I traveled abroad the wagon of a gentile driver who stopped at every tavern along the way to have a drink. We once passed the ruins of a one-time tavern. He halted, entered the broken-down building, and remained there for a long time. When he returned, I asked him, ‘All right! I can understand your wanting to visit a tavern for a drink, but why did you go into the ruins?’
‘I went it’, said the driver, ‘to think about the old days, when this tavern was full of life, and to remember the first-class, strong whiskey they sold here’.
‘That story teaches us the difference between the wise talmidei chachamim and the ignorant. The ignorant waste their youth carousing and become addicted to following their desires. In old age, their bodies become ‘ruins’ and they cannot kick up their heels as thei did in the past. Then it is that they spend their time in fruitless longing. The wise, however in contrast, war against their desires while young, in order to serve Hashem. In old age, when the body is weak and the desires no longer have their former force, they are able to serve Hashem in peace an quiet; nothing troubles them”. (Avanecha Barzel 62)