Evolution has long been the target of illogical arguments that use presumption.

Scientists and creationists are always at odds, of course.

Geometry is beautifully logical, and it teaches you how to think and prove that things are so, step by step by step. Proofs are excellent lessons in reasoning. Without logic and reasoning, you are dependent on jumping to conclusions or - worse - having empty opinions.

Know how and how much to tip people who expect gratuities, even in the case of poor service.

No one would choose to be jerked randomly off task again and again until you have half a dozen things you're trying to get done, all at the same time.

Be able to recognize when you're reading or hearing material biased to your own side.

The magnitude of an action may change not only the strength of its impact, but the direction. If you became a dentist, for example, you would certainly be an asset to our society. But what if everyone became a dentist? Who would bake the bread? Who would build the houses?