tl;dr: David Chisnall recounts trying NeoVim and discovering it silently deleted his Vim persistent undo files by detecting them, wiping them, and replacing them with an incompatible format. When he filed an issue, maintainers responded that the persistent undo format was unstable and users shouldn't rely on it—an attitude he found disqualifying, violating Jef Raskin's First Law that software must not harm a user's work. The post is a reminder that users remember tools that destroy their data, and that respecting on-disk user data is a baseline duty of care.