Persistence is probably the single most common quality of high achievers. They simply refuse to give up. They longer you hang in there, the greater the chance that something will happen in your favor. No matter how hard it seems, the longer you persist the more likely your success.
If you are going to be successful, you need to give up the phrase, "I can't" & all of its cousins, such as "I wish I were able to.
Remember, you and you alone are responsible for maintaining your energy. Give up blaming, complaining and excuse making, and keep taking action in the direction of your goals - however mundane or lofty they may be.