What was the first post-launch fix that actually improved retention?

After a recent Product Hunt launch, I saw the usual pattern strong initial traffic, followed by a drop once the launch window passed.Instead of immediately shipping new features, I spent time watching where first-time users hesitated or dropped off during their initial experience. A few small fixes ended up mattering more than expected.

For builders who’ve been through this phase: what was the first concrete thing you fixed post-launch that noticeably improved retention or repeat usage?

Was it onboarding copy, activation flow, a missing use case, or something you only noticed after observing real users?

Looking to learn from specific examples rather than general advice.