well, I dont think so
I am from a hot country, and there are lots of ppl who feel sad
Actually, it is a nature of human kind to feel a mixture of happiness and sadness
I wont like my life if it is always happy or always sad, it seems as there is nothing to stive to get,no goal, no motives.
Regarding cold climate, may be becoze they miss the sun
while in hot countries sun always shine, heh I notice ppl in England feel very happy when