Expectations always play a major part in how you perceive and appreciate something. I'm not sure why there is so much hate toward this drama or what they expected. I'm not saying that all people should like this one but I've seen on several reviews calling it trash and completely bashing it while many other series are given so much grace and excuses such as "it's because it's a drama" and don't get me started on hyped dramas who promote abuse as love. It has also been said that this drama is full of clichés, and I don't really agree with it being over the top but even so, you can't avoid having some of them or at least it's extremely rare to be able to in kdrama.

To be clear. This drama is for those who want to watch something light and easygoing and not overly complicated. The focus is not dark crime or heavy romance nor is it over-the-top dramatic comedy. It's not perfect but I still found it sweet and enjoyable.

What I liked about this drama is the relationships.
Especially between Yoo Dong Man & Kang Sun Ho but also between Sun Ho and his friends and the dynamic between the colleagues of the professors. The romance is not in the center but I actually like that part. Not every drama needs to be all about the romance. I could relate to Sun Ho not feeling like he had a direction or a dream but also enjoyed seeing him finding and growing those during his time at the university. I liked the part where we saw their training even though I would've liked to see more of that. I liked that the investigation actually moved forward, finding clues and making arrests compared to having a cat-and-mouse game where the suspect always slips right out of their fingers until the last episode. There were some twists and turns but not excessive and they wrapped everything up at the end.

Things I think could've improved the drama.
Exploring Sun ho relationship with his adopted family more. I was really disappointed we didn't get to see more of his brother and their dynamic. I would actually liked to have seen a little more fleshed-out backstories for all of the main leads. That would've given the drama a little more depth.
I think Sun Hos hacking skills could've been used in a more interesting and useful way, it felt like they used it just as a plot starter and then as an afterthought. Also, Kang hees Judo skills, even Sun Hos brother's, were disappointedly really unused.
I wanted to see more of the police university training and them learning useful stuff and improving, also more of the university life in general.

Overall
Take it for what it is, which is an easy-to-follow drama that explores the meaning of the word justice in a sweet and somewhat simplistic light way. It certainly does not deserve to be hated on.
Is it groundbreaking? No. Is it a bit average? Yes. Did I still enjoy it? Yes.
If this is not your cup of tea then just move on to something else.