On takeoff? Usually, although takeoffs are usually kinda fun. But it's nice to hold the hand of my girlfriend (first taking Linda to meet the parents, then Deb a decade later) or wife.

On landing? Always. Most especially with low cloud cover. I have no memory of the plane crash I was on, but it happened during final approach during a storm, and the back of my brain either remembers the event or remembers the circumstances.

When I traveled alone, which happened a LOT in my first job after the Navy? Breathing techniques. "Fear is the mind killer. Fear is the little-death..." Watch the ground coming up (when the sky is clear) or in my peripheral vision (when there was low ceiling). Wait for the bump...