It isn't at all terrifying, the real fun begins if you encounter serious turbulence (sudden zero gravity with an instantaneous +/-20ft drop in altitude, or vice versa 2x gravity as you are suddenly lifted), or during landing and your pilot gets a crosswind that bounces the plane on landing, sometimes crossing it up. My very first flight was a red eye on Peoples Express almost 40 years ago landing in LAX, we landed really hard, bounced, landed again, overhead compartments popped open, carry-on stuff flying everywhere, O2 masks popped out from the ceiling, the plane seemed to get crossed up as the pilot fought to straighten it during the landing. I've flown a lot, never had that happen since.