The true sign of intelligence is not knowledge but imagination.
-Albert Einstein

Intelligence without ambition is a bird without wings.
-Salvador Dali

Just as iron rusts from disuse even so does inaction spoil the intellect.
-Leonardo da Vinci

Every lesson has it's costs, and it is always costlier when the lesson is not learnt, for it will repeat again at higher costs.
-Jensen Siaw

There is no great genius without a mixture of madness.
-Aristotle

Intelligence is the ability to adapt to change.
-Stephen Hawking

For you to insult me, I must first value your opinion.
-Unknown