This is a useful tip!
but also... who has a dir with 777 permissions? Is that something people do nowadays?
Well, everybody has 1777 as /tmp (with the sticky bit).
$ ll -d /tmp
drwxrwxrwt. 20 root root 4096 Mar 3 12:19 /tmp
$ mkdir mytmp
$ chmod 1777 mytmp
$ ll -d mytmp
drwxrwxrwt. 1 luser lgroup 0 Mar 3 12:19 mytmp
My guess would be mounting an NTFS partition - with ntfs-3g it will load everything as 777 just by default, since it can’t translate the permissions.