I'm talking about displacement severe enough to merit a terse, "Flight attendants take your seats!" from the captain or FO. The problem with CAT, as I understand it, is that it is completely unpredictable and can result from mountain rollers, a thunderstorm many, many miles away, or for no discernible reason at all. Minor bumps or continuous light chop is one thing. As a frequent flier, the first thing I'd think of if there was a sudden, violent displacement would be CAT. However, as a long-time flying phobic and, particularly, when I was an inexperienced flier, I'd be thinking, "Oh my god, the plane is broken, the pilot is unconscious and we're all going to die!" That terse and oh-so-serious, "Flight attendants take your seats," made it sound like an emergency. I refer back to the weird mountain-roller "explosion" incident I mentioned earlier -- a number of people actually screamed when it happened. Yes, the pilot told the FAs to sit, but moments later came back on in a nice calm voice and said something to the effect of, "Well, I'm sure you found that interesting -- I know we in the cockpit sure did, but it's actually a normal part of flying and nothing to worry about." Everybody laughed and the atmosphere in the cabin immediately returned to normal.

Two short (I hope) anecdotes: (1) On a flight into Houston, our descent put us right at the cloud tops, clouds, of course, not being the fluffy gentle things we see from the ground. I was in an L1011 which had FA jump seats that faced the first row of coach. This was back in my fearful days (I'm happy to say I'm no longer a flying phobic and haven't been for some years). As we bumped and bounced along, I grew more and more uncomfortable and finally asked the FA if there was some reason for flying at the altitude we were. She said, "You know, I was wondering that myself -- I don't know what that pilot is doing." She picked up the cockpit phone and, more or less, yelled at the pilot. Next thing I knew, we had gained enough altitude to clear the clouds and everything smoothed out.

(2) Having learned that pilots have discretion to ask for more comfortable altitudes, my wife and I were returning from Beijing on a particularly bumpy China Eastern flight. At one point, I rang the call button and asked the FA if he could ask the pilot to find a more comfortable altitude. He looked at me as if he didn't understand, and my wife (who is Chinese) repeated my request in Mandarin. The FA shrugged his shoulders and said, "I'll ask," and went up front. He returned a while later and said, "We don't do that."

There are people who like roller coasters. And there are people who really, really don't.

Once, on a trans-Atlantic overnight flight that took us pretty far north, the pilot made an announcement directing our attention to the aurora borealis, which was particularly vivid that night. I don't think anyone complained -- everyone near a window stared out at the sight transfixed, and those on the aisle were practically in the laps of the middle seat pax trying to catch a view. Folks on the other side of the plane, though, looked distinctly unhappy, not at being woken up, but at missing a rare sight.

I agree -- tempering PA announcements is an art. On the whole, though, unless it's an absolutely routine flight -- perhaps at night over the desert when there is, literally, nothing to see -- and so smooth that you could cut diamonds, I'd rather the pilot err on the side of too many announcements than too few.