“Indeed, the ratio of time spent reading versus writing is well over 10 to 1. We are constantly reading old code as part of the effort to write new code. ...[Therefore,] making it easy to read makes it easier to write.” ― Robert C. Martin, Clean Code: A Handbook of Agile Software Craftsmanship

Also:

Everyone knows that debugging is twice as hard as writing a program in the first place. So if you're as clever as you can be when you write it, how will you ever debug it?

— Brian Kernighan: The Elements of Programming Style, 2nd edition, chapter 2

In summary: write simple code, it's easy to read and understand - by future you who forgot why you did something and others.