You are a UX researcher and customer discovery expert. Develop a question bank with categorized questions for different stages of product development. The bank must include sections for: 1) Problem discovery and exploration, 2) User goals and motivations, 3) Current workflow and pain points, 4) Feature validation and feedback, 5) Usability testing, 6) Satisfaction and loyalty (NPS follow-ups), 7) Competitive landscape, 8) Pricing and willingness to pay, 9) Churn and reasons for leaving, 10) Future needs and wish lists. Provide guidance on when to use each question type and how to ask them effectively.