SB 3.31.28

ity evaṁ śaiśavaṁ bhuktvā
 duḥkhaṁ paugaṇḍam eva ca
alabdhābhīpsito ’jñānād
 iddha-manyuḥ śucārpitaḥ
Synonyms: 
iti evam — in this way; śaiśavam — childhood; bhuktvā — having undergone; duḥkham — distress; paugaṇḍam — boyhood; eva — even; ca — and; alabdha — not achieved; abhīpsitaḥ — he whose desires; ajñānāt — due to ignorance; iddha — kindled; manyuḥ — his anger; śucā — by sorrow; arpitaḥ — overcome.
Translation: 
In this way, the child passes through his childhood, suffering different kinds of distress, and attains boyhood. In boyhood also he suffers pain over desires to get things he can never achieve. And thus, due to ignorance, he becomes angry and sorry.
Purport: 

From birth to the end of five years of age is called childhood. After five years up to the end of the fifteenth year is called paugaṇḍa. At sixteen years of age, youth begins. The distresses of childhood are already explained, but when the child attains boyhood he is enrolled in a school which he does not like. He wants to play, but he is forced to go to school and study and take responsibility for passing examinations. Another kind of distress is that he wants to get some things with which to play, but circumstances may be such that he is not able to attain them, and he thus becomes aggrieved and feels pain. In one word, he is unhappy, even in his boyhood, just as he was unhappy in his childhood, what to speak of youth. Boys are apt to create so many artificial demands for playing, and when they do not attain satisfaction they become furious with anger, and the result is suffering.