I went through 1star ratings and maximum was talking about " portraying mental illness in a wrong way". Well let me be very clear, in this drama nothing is offensive. You might feel irritating and messed up about the female lead character but that's how they wanted to portray and you will definitely find the reason behind it. Yes, the love process might be little bit slow because ofc it's a drama, damn DRAMA!( Now Q yourself, what is the meaning of drama?) Nothing is shown overdramatic or something else because yes, there are lot of psycho people who does dangerous things. There are people who are emotionally unstable because the past never let them free. There are people who cannot overcome easily and takes a long time. This drama shows you everything. When you keep on watching the drama you will slowly find the reasons for why people behave in a particular manner.
I don't regret watching this. I actually loved it. I loved Everything. I don't understand why people are disliking it so much. Be patient and continue watching it. You will also learn a lot of things that matters a lot in your life. :)