Do not let your fire go out, spark by irreplaceable spark, in the hopeless swamps of the approximate, the not-quite, the not-yet, the not-at-all. Do not let the hero in your soul perish, in lonely frustration for the life you deserved, but have never been able to reach. Check your road and the nature of your battle. The world you desired can be won, it exists, it is real, it is possible, it’s yours. - Ayn Rand
That quotation was taken from Atlas Shrugged, a novel which everyone ought to read (in my opinion!). It's more meaningful and relevant than ever.