What are the most sought after Kennedy half dollars?

Are you familiar with the most sought-after Kennedy half dollars in the market? I'm curious to know which ones collectors are particularly eager to get their hands on. Could you provide some insight into what makes these coins so valuable and desirable? Are there any specific years, mint marks, or conditions that make them stand out from the rest? I'm eager to learn more about the world of Kennedy half dollar collecting and how to identify the most valuable pieces.