It's going to sound like a hackneyed saying, and yes, it's definitely the opening line of "Hanging Tough," but when the going gets tough, the tough get going.
If you're really looking to get something done, then the last thing you're looking for is an excuse to back out. Instead, you're looking for every excuse to actually make it happen. And even if you fail in making it happen, you're going to feel pretty darn good that you did everything in your power to accomplish your goals.
It's the reason why Rocky affected so many people, even though [spoiler alert] Apollo Creed beats him at the end, he left his heart out in the ring and played out love to the highest degree with Adrian. The dude is a champion.