Lots of people limit their possibilities by giving up easily. Never tell yourself this is too much for me. It's no use. I can't go on. If you do you're licked, and by your own thinking too. Keep believing and keep on keeping on.
Norman Vincent Peale (May 31, 1898 December 24, 1993) was a Christian preacher and author (most notably of The Power of Positive Thinking) and a progenitor of the theory of "positive thinking".