It's also vital to talk non-pilots through manouvres such as:
"We'll dive for a bit of speed and you'll feel the 'G' come on as we pullup... here we go, diving for speed, level, and pulling up n-o-w to about... this attitude, then r-o-l-l the aeroplane all the way around...isn't that fantastic... and then gently ease back up, up and here we are straight and level again".
It's the unexpected 'G' or sudden manouvre that they don't like. Who would?