Short Answer: Because he had low elf-esteem! 🧝♂️😔
Explanation: The play on words here is that "low elf-esteem" sounds like "low self-esteem," which means feeling down or lacking confidence. In this funny scenario, Santa's helper (an elf) is feeling sad because he lacks confidence in himself. The use of the 🧝♂️ emoji adds a playful and cheerful touch to the answer.