What's your favourite quote?

Usually by someone or something you came up with. Something hard hitting, humourous or worth a thought.

I often say,

"What you see is a perspective and not necessarily the fact. What you hear is only an opinion and not necessarily the truth."

I have a Facebook page where i post quotes and in one i write, "Our worries are nothing but a figment of our imagination."

My favourite book where i find really good quotes is "The Meditations by Marcus Aurelius"