Gwendal is constipated.
That would explain his (almost) perpetually bad mood and poker face. The relatively rare moments where he's knitting and happy are just times when he managed to poop.
The entire world of KKM is a drug-induced hallucination.
Yuuri is frustrated with being bullied, and experiencing some Gayngst which he won't admit to himself, and in order to escape reality, he takes hallucinogenic drugs.
Or well the world of KKM could be as well be A Parallel World
Not that would be make sense, but it would be better than a drug-induced halluncination
