I stopped $ rm -rf ./things -and instead do- $ mv ./things /tmp and just forget about it. Yeah yeah, it won't work on a server, but for a home system that reboots occasionally, it should work fine.
I've learned that nobody and nothing should use /tmp, on account of it being 777. The idea is that Mallory can set up a symlink from an anticipated filename ("things" in your example) to an important file or dir. So writing to /tmp/things destroys the symlinked file/dir.