Never complain and never explain.
You never know what motivates you.
Who seeks shall find.
If you think you can do it, you can.
After a storm comes a calm.
The wise does at once what the fool does at last.
Go for it now. The future is promised to no one.
What you do today can improve all your tomorrows.
Leap, and the net will appear.
Without hard work, nothing grows but weeds.
The frontiers of knowledge in the various fields of our subject are expanding at such a rate that, work as hard as one can, one finds oneself further and further away from an understanding of the whole.