After I got into guns and shooting, after a few years my wife said she wanted to go to the range with me and "see what it's like". I took a .22 revolver and a .32 semi-auto for my wife to shoot, and a .38 Special for myself. The place was packed and they put us in lane 2 of a 15 lane indoor range.
My wife stood behind me while I shot a couple of cylinders of .38 special. Then she gets in front of me and I'm starting to get her adjusted to start shooting the .22 revolver. The guy next to us in Lane 1 who has not shot until now, pulls out a long barreled 460 or 500 with the barrel sticking past the barricades in between us and shoots the full cylinder at about 1 second per shot. Every round that goes off is like us being slapped in the face. My wife backs into me trying to get away from it. I back off too. My wife is in tears...shouting that she wants to get out of there...and we leave. She's in tears out in the showroom area. She has never been back, never seen me shoot, has no desire to ever be around guns again. Scared her to death.
I have always carried a piece of paper when I am shooting a pistol like that at an indoor range (I had a .44 Magnum with 8 3/8" barrel) - that I show to the people on either side of me (when convenient) to let them know and won't be startled.