What is the best quality bolt?

What is the defining characteristic that separates the best quality bolt from the rest? Is it the material it's made of, the strength it can withstand, or the precision of its threading? And how does one go about selecting the most optimal bolt for a specific application, ensuring it meets all necessary criteria for safety, durability, and functionality? Could you elaborate on the key factors that contribute to a bolt being considered the best quality, and provide some guidance on how to make an informed decision?