How would I react? I'm a rational guy. When the going gets rough, I look around for the Flight Attendants. If they're not terrified, then neither am I. If they're screaming, I scream.
I admit that fear is most manageable when it's brief. Losing an engine every half hour would be difficult to shrug off.
My two emergencies were both mercifully brief. In the past 3 years I've been on two aborted takeoffs from SFO on transpac 747's. Must have been just below V1 'cause by the time we shuddered to a halt there was no runway remaining. In fact, the March '07 event popped all the heat plugs in the tires, requiring a 6 hour delay to swap them out.
Supposedly a full-time pilot would only have to abort once every seven years. Just my luck. So, plan your transpacs on the days I'm staying home.