do you have to watch the previous season to understand this one ?
Yes because Yumi evolves as a character and season 2 starts at the end of season 1. It's a journey. I suggest start with season 1 and if you like it, you'll also like season 2.
2 days back people were like I like babi more but now as soon as woong came they are like he has more chemistry…
I like both in different ways. I really think Woong could be perfect for Yumi but they have to learn to communicate more openly. Woong was under so much pressure (and evidently still is)... He couldn't cope with his own crisis and Yumi's jealousy. Babi is patient and kind... Plus, they have similar interests. We have to see how the story progresses. I'd still like her to give Woong a second chance if he can get his act together.
I am so annoyed how they made the FL so useless, even the SFL is so much more interesting to watch and her character…
Yeah, I agree. She somehow doesn't fit. I think her purpose is to bring a lighter quality to the drama, but it's too light that she just seems ridiculous and boring. A different FL/actress/style of character could have given this drama much more.
1 
It's a journey. I suggest start with season 1 and if you like it, you'll also like season 2.
Yumi has been swept off her feet by Babi, but I'm not convinced it's true love from her side.
Can I ask, does LHZ get a makeover during the drama?