Page 220-221 in “21 Lessons for the 21st Century” by Yuval Noah Harari:
If you want to go deeply into any subject, you need a lot of time, and in particular you need the privilege of wasting time. You need to experiment with unproductive paths, to explore dead ends, to make space for doubts and boredom, and to allow little seeds of insight to slowly grow and blossom. If you cannot afford to waste time — you will never find the truth.
Apropos allowing little seeds of insight to slowly grow and blossom, compare: “What Gregor Mendel tells us about thinking.“