Thanks to them, there are few thruths in this world I was lucky enough to find out:

Firstly, to mature means a sudden falling into cruel reality.
Secondly, getting adult isn't anything bad. As 20 years old now I feel as if I got younger. I talk more and I got a bit more childish. 
And lastly - sometimes they find girls too complicated no matter how old we all get.

“Being a teenager is a stormy period, because we don’t know the answers. We don’t know what we really want, who really loves us… and who we really love. We struggle to find the answer. And finally, when we miraculously find the answer, we’ve already become adults and undergone big and small goodbyes.”

– Reply 1997

Teaser:

https://www.youtube.com/watch?v=ZPpi84HHzk4