Why did, and do, teachers not use everyday example to demonstrate the concept of symmetry? Just about everything we use or experience is symmetrical. Math geeks like me know this because we are constantly aware of the impact of symmetry on our lives. Just about every face on every animal is symmetrical; every door you walk through or window you look through is symmetrical. Most cars or trucks we drive are symmetrical as are most houses in which we live.
Fruits and vegetables are symmetrical as is most packaging that things come in. Fractals are symmetrical and so are road signs. Furniture is symmetrical as are appliances. Light bulbs and candles are symmetrical as well as plates, bowls and forks. Knives are symmetrical about a plane of symmetry. Drawers and drawer handles are symmetrical as are most tools like screwdrivers and hammers; again a plane of symmetry.
Some words are even symmetrical; words like madam, level and radar. And, of course there are phrases and sentences that are symmetrical like: "A man, a plan, a canal: Panama".
One of the sad things about our symmetrical world is our sometimes inexplicable intolerance for things that are not symmetrical when they should be. This is perhaps most vividly illustrated by the difficulties faced by Auggie in the wonderful book Wonder. Sometimes we must make sure we don't let our inherent need for symmetry get in the way of being a good person.