The sun does make people lazier, according to my professor,lah.
Quick thought : I remember when my Geography professor once told us in that lecture hall, about the relationship between climate type and development of a particular country. It is observed that the closer a country to the equator (such as India, Ghana etc) , the less developed a country prone to be. According to him, that comfy climate makes citizen lazier and thus, discourages discovery towards science and technology.
Yeah, but I think what make people lazy are tv, xbox 360 and a lot of KFC, which absolutely comes from your (the Geography professor) country.