"At the start of my book, Learning JavaScript Design Patterns, I say "good code is like a love letter to the next developer who will maintain it". It is an intimate correspondence, from one developer to another, spanning time and space."

Seriously?!

It's simple. It's a matter of respect, and treating others as you would like to be treated. It's no fun trying to figure out the "why?" of some code you've inherited responsibility for. It can be frustrating and time consuming.

So why would you put others through it. Make the code and the reasoning behind it as clear to the next dev as possible. Explain it with comments. Refer to issue links. Make it so that there's minimal - preferably zero - unnecessary digging for the next poor soul who'll work on it.