Attention-deficit disorders seem to abound in modern society, and we don't know the cause.

Loving behavior contributes to the group at the expense of the individual. Competition contributes to the survival of the individual at the expense of the group. In the garden of life, some people are more like flowers, and other people are more like weeds.

Understand why casinos and racetracks stay in business - the gambler always loses over the long term.

A fool is someone whose pencil wears out before its eraser does.

Yes. The original argument is defective. Substitute the word 'male' for 'gay,' and you'll see the flaw: 'Male people cannot be normal. If everyone were male starting tomorrow, the human race would die out, so being male cannot be nature's intended way.' Or you could substitute the word 'female.' In either case, the argument makes no sense: Being male or female is perfectly normal.

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

Know the difference between principles based on right or wrong vs. principles based on personal gain, and consider the basis of your own principles.