One of the most common mistakes for any English speaker in Italy is unfortunately one that to this day, I continue to make (after 18 years!). You call someone you once met for business purposes. They tell you that he's not in ("non c'è).
You want to understand if he's no longer with the company, or simply, not in. So, you ask, "Oh-ok, non c'è più?"
The person at the other end never knows quite how to take this remark -- as you just inquired whether that person is no longer -- or not with us anymore -- as in, 'he's dead'.
-- Francesca Maggi, Burnt by the Tuscan Sun (Rome)