You never know what motivates you.
Never complain and never explain.
Be kind whenever possible. It is always possible.
The wise does at once what the fool does at last.
It's always too early to quit.
By failing to prepare, you are preparing to fail.
Be gentle to all and stern with yourself.
Wherever you are - be all there.
Either you run the day or the day runs you.
Well done is better than well said.
Imagination is as vital to any advance in science as learning and precision are essential for starting points.