I spent a week building a counter program in Anchor. By the end, every user had their own account, a global config singleton controlled whether new counters could be created, and a close instruction returned the rent deposit back to the wallet. None of that would have been possible without Program Derived Addresses. This post is what I wish someone had handed me on day one. The Problem PDAs Solve On Solana, programs are stateless. If your program needs to remember something, a user's score, a va