joie de vivre
Ebullient happiness and love of life. From French, literally meaning "joy of living." He isn't the most responsible person I've ever met, but his joie de vivre is positively infectious.
ˌjoie de ˈvivre
(from French, written) a feeling of great happiness and enjoyment of life: After the depressing events of the last few months, Mina felt that it was time to put a little joie de vivre back into their lives.This French phrase means ‘joy of living’.