I am not sure if it is possible to be "more than everything" but in sports we always hear about giving 110%. If that statement is true then, attitude is more than everything when it comes to sales and success.
The thing that we must remember is that we cannot turn attitude off. Our mind is always creating and our attitude is the road or path that leads the way to what we create. We can't do affirmations and get excited and then feel the fear in our stomach when a challenge comes along.
Give thanks for the challenge. Praise the challenge. In the Bible it says, "Let there be Light.." We cannot affirm that there be light or success or anything without something to contrast that light or success against. The Light came out of the darkness. Our success and many times our greatest successes come from our failures. The best attitudes are attitudes of "can do, will do, and gratitude" (I like that, just made it up as I am writing !)