From: SelfDocumentingCode
Format your code!
Rationale:
Code formatting is very important in simplifying code. Presentation is important in all forms of communication because it provides organization and a clear path from one idea to another. In something as complex as a codebase, every little bit helps.
Also, programmers should focus on solving the problem and not on graphic design. Having a fairly consistent set of code formatting rules frees the coder from having to waste brain cycles on such pithy concerns.
Subsections:
See: CodingStyle