***SPOILER ALERT***
First of all, the drama is a perfect mystery. You'd never know which character is good or bad. It kept me hooked from the starting to the end. The first season was indeed very toxic, I agree personally. The last 5 episodes of season 1 mentally affected me like I was being all rude and arrogant. But the reason was that I watched all 5 of them in one day, and because of having a toxic day I was acting that way. But trust me, the second season paid all for it.
The second season was wayyyyyyyy better than the first one and it showed more interesting plots. The third season was even better! Whoever is reading this, I recommend you to stop reading other reviews and start it right away!
Honestly, the drama showed how money, fame, and connections are wrongfully used. All the rich and bad characters would bribe mostly all types of people- normal ones, real-estate officers, policemen, politicians, and even school teachers! I would definitely recommend it to people who want more of a drama content instead of normal romance cliches. There are two couples who you'd ship after watching Penthouse: Bae Rona-Joo Seokhoon and Shim Suryeon and Logan Lee.
Thanks for reading :D. Now go and watch Penthouse before you lose interest :/