The so-called growth probably means gradually understanding things one couldn't understand before and gradually understanding people one couldn't before.
For example, Zhou Wang vaguely remembers that when he graduated from high school and attended a classmate's graduation banquet, he thought he had a pretty good relationship with this classmate, often joking and playing around.
But when he went to toast at that time, Zhou Wang, who wasn't very good at drinking that year, impulsively downed a full glass of baijiu in one go, only to find that the other person merely sipped it.
The word "sip" might not even be right, perhaps "lick" is more appropriate.
Back then, Zhou Wang was filled with resentment, feeling that he was being underestimated by the other person. Now, thinking back to the past, he couldn't help but smile it off.
