Don't take tomorrow to bed with you.

The only real mistake is the one from which we learn nothing.

Criticize the act, not the person.

If you're happy, don't worry you'll get over it.

Only from the heart can you touch the sky.

Most of what matters in our lives takes place in our absence.

If you only read the books that everyone else is reading, you can only think what everyone else is thinking.

A friend to all is a friend to none

If we know exactly where we're going, exactly how to get there, and exactly what we'll see along the way, we won't learn anything.

Every aquarium will eventually leak.

Good means not merely not to do wrong, but rather not to desire to do wrong.

Admiration is the daughter of ignorance.

Things which matter most must never be at the mercy of things which matter least.

Those who see the invisible can do the impossible.

If you don't stand for something you will fall for anything.

As our case is new, we must think and act anew.

The essence of knowledge is, having it, to apply it; not having it, to confess your ignorance.

If we do not lay out ourselves in the service of mankind whom should we serve?

Real knowledge is to know the extent of one's ignorance.

We may encounter many defeats but we must not be defeated.

How often I found where I should be going only by setting out for somewhere else.