From "The 8th Habit" by Stephen R. Covey
Four simple assumptions - one for each part of our nature - to lead a better life:
1. For the body - assume you've had a heart attack; now live accordingly.
2. For the mind - assume the half-life of your of your profession is two years; now prepare accordingly.
3. For the heart - assume everything you say about another, they can overhear; now speak accordingly.
4. For the spirit - assume you have a one-on-one visit with your Creator every quarter; now live accordingly.
I like it.