It's bad writing, however naturalistic it's written, that's where you have to do your best acting.

All you can do is to do your best.

If you try to do your best there is no failure.

Always do your best.

You can only do your best. That's all you can do. And if it isn't good enough, it isn't good enough.

It is not enough to do your best; you must know what to do, and then do your best.