Joie de vivre

Joie de vivre is a French phrase often used in English to express a cheerful enjoyment of life.
Usage and Example:
    One of your best collegue is retireing today.He is the best person you ever known, commitment at the top,highly intellectual,always motivational,happy all the time in his personal and professional life.Simply you see him as a perfect role model on how to enjoy life in all ups and down.

On the farewell speech you can say like "It is difficult to imagine our company without his passion, commitment, joie-de-vivre and intellect".