I don’t buy this. Feels like a non-problem or a very first world problem to even analyse and with the exception of lights, nothing else seemed plausible

Why do you think that? What knowledge/leaning do you have that would add weight to your opinion?

Really, you don't find it plausible that environment could affect mood?

I dont know if the hypothesis in the paper is correct, but it seems clear that environment can affect mood in some cases. There is a reason why night clubs and libraries are decorated differently. From there it seems very plausible other elements of environments could have an affect (perhaps subtle) on mood.

So you thibk light might affect, but something visual.. that we see does not?