Make light of it all you want, it has happened. Use bird shot for birds.
I'll shoot at the dry wall in your house with my 12 gauge.
Have any radiators? How about window cranks? Nail or screw heads? How about nail plates(to protect pipes or wiring) in your dry wall? Small, light shot can and will bounce. Spend any time at a range, indoor or out, with someone shooting birdshot and you will get hit by bouncing shot eventually.
I have spent an enormous amount of time shooting birdshot. I hunt, shoot trap and reload as a hobby. I have never been hit by a birdshot ricochet. I have been "rained upon" by birdshot while duck hunting, but that's not a ricochet.
I'm not saying a birdshot ricochet is impossible, but it is not as likely as you imply. There are plenty of knowledgeable people who advocate birdshot for self defense because it is less likely to cause serious collateral damage.
All things considered, I think it is appropriate to make light of your assertions.
Buck shot will bounce from radiators and metal window mullions too. It has also happened. I'd gladly trade an eye for my life or the life of a loved one. Your scenario is far less frequent than the wounding or killing of innocents on the other side of the intended target by bullets that have already passed through the intended bad guy. The idea is to deliver all the energy carried by the projectile, regardless of what it is to your intended target, delivering a stopping blow, and then not have it continue on through to an unintended one.