I can't preach enough how much this is one of the best character driven stories to be made in the modern era. Part of it is credit of the source material, for sure, the mangaka who made it is extremely sensible and wrote it beautifully. But studio Shaft has shown us how to adapt things well, first with the Monogatari Series and now with Sangatsu no Lion.
There's enough good stuff here for me to make a book about every episode, but I must say that one thing in particular just made me lose my marbles, and I'm talking about the last episode from the second season. I won't spoil anything here, so all I can say is: It has the best prologue to a last episode that was ever made. And I'm not exagerating just to create shock value, I genuinely believe it and extend this to any other kind of episodic show, be it anime, live action, series, anything.
If, for some reason, you never watched this anime, do it right now. Also, don't think I hyped it too much with all I just said, it will surprise you with everything else before getting there.