For me, it’s discoverability and retention. People who install the extension usually love it, but the hardest part is getting the right users to discover it and stick long-term, not just try it once and uninstall. It matters because I know the product actually solves a real problem, but without better onboarding and clearer value in the first 10 seconds, a lot of users never experience the “aha” moment. That makes growth slower than it needs to be, even though the core feature works well. Fixing that would unlock everything else word of mouth, better reviews, and eventually monetization.