I am somewhat of a quote collector. These are some of my favorites:
"You can have no impact on society until you first change yourself." ~Nelson Mandela
"In insanity, we do not discover anything new and unknown; we are looking at the foundations of our own being, the matrix of those vital problems on which we are all engaged...." ~Carl Jung
"My life belongs to the whole community, and as long as I live, it is my privilege to do for it whatsoever I can. I want to be thoroughly used up when I die, for the harder I work, the more I live. I rejoice in life for its own sake. Life is no 'brief candle' to me. It is a sort of splendid torch which I have got hold of for the moment, and I want to make it burn as brightly as possible before handing it on to future generations." ~George Bernard Shaw
Not all psychology related, but the Shaw quote gives a lot of explanation as to why I am in the field.