The issue I had with One and Only was the lack of believable chemistry between Ren Jia Lun and his female co-star, not to say he's a bad actor but he's simply unconvincing as a love interest.
Sadly, that is the same grievance I have with Miss Crow With Mr. Lizard. Funny enough, he had more chemistry with the second male lead than he did with the FL which is disappointing because Xing Fei, IMO, is an actress who actually knows her craft and she completely embodied the lovable, tenacious but naive Jiang Xiao Ning.
So, having read some reviews today, my understanding is that Ren Lun is married and his contracts stipulate there be minimal to zero intimate acts like hugging or kissing; they even have a stand-in for when those sorts of scenes are unavoidable.

How then can an actor in a modern romance truly separate his real-life persona if he's constantly on guard to not inadvertently make it seem as if he's romantically interested in his on-screen co-star? Look, I don't need on-screen kissing or hugging because there's so much that can be done with stares and subtle body language. A good example is Li Hong Yi's flirtatious performance in Love Better Than Immortality which nearly melted our screens. All Li Hong Yi did in the first half of LBTI was stare at Zhao Lusi and I swear I could feel the tension between them. THAT is how you do non-tactile acting. Not this forlorn, detached look that Ren Jia Lun has in all his romance dramas.