Small habits:

When the airplane is about to take-off some kiss their Rosemarie’s; others just cross their fingers and say a small prayer to themselves; others close their eyes and look up; others just knock three times the floor with their feet. But when the plane is about to take-off I´m just doing all the emergency summery in my head in case of a crash landing or ditching.  

(I don´t own the above picture)