These were the wise words of Gustave Flaubert (1821-1880), French novelist of the realist period and author of Madame Bovary (1857).
It is so easy to become paralyzed with fear of "making a mistake" or "ruining your art" with one false move. I have felt that fear many times, but have learned to embrace it. I have resolved to work in many layers, which makes everything a possibility, rather than a mistake.
For example, have you ever worked with tissue paper? The great part is how the dye runs in unexpected ways. Using white glue watered down, I applied the tissue pieces to the canvas here, and right from the get-go, the colors began to leach out. I simply continued on with my collages and any really delicious areas I left uncovered to work in "later". I can't tell you how many artworks have then been complimented by these backgrounds that I scanned in.
Using your imagination and creativity, you can turn accidental tears, spills, rips, and smudges into something new and beautiful. Rather than being discouraged by accidents, allow that accident to lead you through in your art-making. Embrace accidents; accidents can become the portal to a new discovery or a new masterpiece.
I will close with another quote:
"All painting is an accident. But it's also not an accident, because one must select what part of the accident one chooses to preserve." -- Francis Bacon