Rajkumar Hirani, the director known for creating magic on screen with movies like Munnabhai MBBS, Lage Raho Munnabhai, 3 Idiots. Normally movie directors come off as hot-headed people who bark and scream orders at everyone around them. But reportedly, Hirani is not like that.
The director who is currently in the process of making P.K. starring Aamir Khan, is supposedly very calm on sets. He never panics nor makes anyone panic. When asked about it, Hirani attributes his calm nerves to the magical drink- Green Tea.
Along with the numerous health benefits green tea gives, it also calms the helmer greatly. That is the reason behind his ever-present smile, which is there even on most stressful scenarios on sets.