I also like this sentence. Because a person needs this kind of concentration if he wants to do a good job. If you think you can do it at will, you'd better not do it. Otherwise, you may not do it well. Completion and doing well are completely two concepts, and anyone will expect perfection. Of course, we can be perfect, which is the best, but if we can't be perfect, we must be the best. That's what this sentence means The attitude towards a thing is to think about doing it in a good direction and try to do it.