"The rule for all of us is perfectly simple. Don't waste time bothering whether you 'love' your neighbor; act as if you did. As soon as we do this we find one of the greatest secrets. When you are behaving as if you love someone, you will presently come to love him...
The same spiritual law works terribly in the opposite direction. The more cruel you are, the more you will hate; and the more you hate, the more cruel you will become — and so on in a vicious circle for ever.
Good and evil both increase at compound interest."
– C. S. Lewis, Mere Christianity