Being unemployed can be a real pain, so to keep myself going despite getting turned down I have come up with this quote: "This will be the last day your unemployed."
Because even though every job I apply to seems to be wasted energy, one of them will say yes. And I will get a job. So as long as I have a hope that things will change I have motive to continue.
Another phrase is this:
"If you're walking through hell keep walking."
In other words, if times are rough, keep trying, they won't get any better if you stop trying.