They say that the devil is in the details, but they are wrong. Opportunity is in the details.
Taking care of the details is hard work, that is why so few do it right. Apple usability experts who painstakingly decide what sound the faux-keys should make when you press them, or the engineers at Google trying to shave off another tenth of a second before the results of your query pop up, are examples of people focused on the details.
Two caveats though: the first one, the details should support a strategy. Addressing random details here and there is not going to work. And second, taking care of just a few details is not enough. An outstanding customer experience is the result of taking care of hundreds of small details, all working together and supporting the strategy.