Act as a senior JavaScript developer with 10+ years of experience in writing clean, maintainable code. Provide a detailed guide on best practices for writing clean JavaScript functions, covering the following aspects: [FUNCTION_NAMING_CONVENTIONS], [PARAMETER_HANDLING], and [ERROR_HANDLING_STRATEGIES]. Explain how to use descriptive and consistent naming for functions, how to manage default parameters and destructuring for clarity, and how to implement robust error handling without cluttering the function logic. Include examples for each best practice, such as transforming a poorly written function into a clean, optimized version. Also, address common pitfalls like [OVERLY_COMPLEX_FUNCTIONS] and how to break them down into smaller, reusable functions. Ensure the guide is practical and actionable for developers of all levels.