Recommendations

both have a similar feel to it. Jenius focuses more on investigation and sci-fi while Simple Man crosses many genre from sci-fi to investigation, action, mystery, medical and paranormal. Personally, I prefer Simple Man over Jenius but both are really good dramas if you are into cleverly made quality mystery, investigation type dramas.

Plots of both stories are really similar. Both are about unfortunate love in Joeson era that repeats again in our time to have happy ending. There is a little of fantasy also: mysterious time travelling in Rooftop Prince, and mermaids in Legend of the Blue Sea. Main characters have troubles adapting to modern world. And after all both series have charming love story.

Teachers with secret identities.
Yankee students.
Life lessons.

Both contain female doppelgangers belonging to opposite ends of the social pyramid, where the poor one must take the place of the rich one in a relationship with the rich lead without letting anyone know

Both involve corrupt politicians, crazy royals, and concubines. The Treacherous is a lot more gritty, but both explore themes of revenge, lust, greed, desire, and power.

Revenge plot galore, great productions, great acting (personally like Nirvana in Fire a bit more because it felt more cohesive and Hu Ge was an amazing actor... however, same can be said for luo jin in The Princess Wei Young)
The romance in nirvana in fire is more toned down than in WeiYoung. Both are highly recommended if you like smart heroes/heroines, political drama, and revenge

If you want to fill the void that Scarlet Heart Ryeo left, this drama is a great reliever. Like Scarlet Heart, it is a historical drama wherein several princes are fighting for the throne and surprisingly *insert the sarcasm* they are also vying for the love of the heroine. But what makes it better is that it is well - written. It has 54 episodes, which I hope you have the patience to finish, so it isn't that rush, unlike you-know-who. The heroine in the story is so much better. We’re at the point in the story where our heroine is being stomped on and typically, she’d lose heart or stay cheery and upbeat in spite of her circumstances. But not Wei Young. She’s more of the, “You might have the upper hand now but I’m still not taking your shit.” type heroine. All in all, JUST WATCH IT :)

Both star Jung Woo Sung as the main lead suffering from memory-loss.

Both take place in convenience stores with weird characters and strange occurrences happening regularly.

contract marriage relationship that brought the couples fall in love.

Both of the female leads are known as wei wei. The drama/movie have the same feel. except that one smile is very alluring is a little more light hearted.

The female leads are known as wei wei. They are both really cute and just kinda almost have the same feel.

It just has the same feel with the main male leads being the same. He helps the female lead with their profession. When a snail falls in love is a little less on the romance though.

There are a lot of similarities between these two. First of all the main female lead is the same actress and the second male lead in both of these is the same. If you watch cruel romance, remember ying dong? Well his brother in cruel romance is playing his father in stay with me. I find that a bit weird, but his character still does everything he can for his family. Also the main lead in here also does so much for the female lead in secret, like in cruel romance. The main female lead does some crappy things to the main lead as well. Also there is the situation of "killing" her father.

They both have to deal with amnesia and misunderstandings between the main leads.