I thought S2 was better than S1 because the characters became more mature and the storyline allowed us to see the characters on deeper levels; putting focus on mental struggles, trauma, and survivor's guilt.
S1 was your cliché high school drama where I felt like feelings were forced out of the female lead's need of comfort.
Whereas S2 is so much deeper! Depicting a more mature and healthy romance, where you let feelings grow organically and naturally with The Love Alarm app as a variable/obstacle, along with the characters' mental struggles and growth. There's a lot of insightful hidden messages in this season and I've never felt more satisfied watching a romantic drama!
So if you like typical cliché high school dramas, I think there are better shows out there for that.
But if you wanna watch an atypical but more organic romance drama with focus on mental struggles and with an interesting sci-fi element of a Love Alarm app (which points a lot of criticism to today's social media and technology dependence). I would totally recommend this show!