Simplicity is Hard
The instructions for Atari’s Star Trek game were only four words:
"Insert Quarter. Avoid Klingons."
It takes a lot of work to create something that needs so little guidance.
Complexity is easy, because it’s often a lazy way to solve problems. Just add another line to the instructions. Or add that new feature without considering how it impacts the user experience.
The hard thing is distilling what you’re making down to its essence so that it’s intuitive.
Your work is finished when it’s so clear, it needs little explanation.
See also: Subtractive Solutions