Happiness

H.L. Mencken - A wealthy man is one who earns $100 a year more than his wife's sister's husband.

Ending matters a lot for memory. 90% bad stuff + 10% good stuff in the end is much better than 90% good stuff + 10% bad stuff in the end.

1. The brain is the source of mental life, but we don't know how this happens.

2. About a half of the variants in personalities of different people are due to genetic factors, but we don't know how the other half happens.

3. The social influences are important to induce and drive people to do certain things. But some people are immune to these social influences.