From Paulo Coelho’s The Alchemist:

“It’s called the principle of favorability. When you play cards the first time, you are almost sure to win. Beginner’s luck…. Because there is a force that wants you to realize your Personal Legend; it whets your appetite with a taste of success.”

Then, much later:

“It seemed as if what the old king had called “beginner’s luck” were no longer functioning. In his pursuit of the dream, he was being constantly subjected to tests of his persistence and courage. So he could not be hasty, nor impatient. If he pushed forward impulsively, he would fail to see the signs and omens left by God along his path.”

When things get difficult, it’s a sign that you’re probably making progress.