Both the main leads and the second leads are the blandest characters in the series. Sure, they are "attractive" but they're not a bit charismatic, they don't have a personality outside the cliché. Kuea is supposed to be a "bad boy" that likes bikes and music, his worst fear is that Lian won't love him because he is "different", excuse me different how? literally, his personality doesn't change, he only has a few hobbies that are "not the norm".If he was similar to Payu from Love in the air I would have understood the point but he's like every other bottom out there except he likes bikes.
The plot is what I dislike most about this series. In the first episode, Lian rejects Kuea saying he doesn't love him and doesn't want to marry him. First, when I watched this i was like, okay, he does love him but he has a secret, that will be revealed in the last episode, that is the reason he has to say that. But he doesn't really have a reason for rejecting him, Lian expends the rest of the series trying to get back together with Kuea, so what was the point in rejecting him?
He explains that he doesn't like him acting like a doll (which he does because Lian doesn't pay any attention to him), but you could just expend more time getting to know him. Not saying you don't want to marry him just to be chasing him, begging him to marry you just a couple of days later?

It was exasperating, like the whole point of the series is the PDA.

The second leads more or less have the same plot, like nothing really different here.

The only charismatic characters are the thirds leads, Syn and Nuer, but they have five minutes of screen time in the whole series.