When a user changes his own account password, the system will keep his login keychain password in sync.

When performing a Safe Boot, OS X doesn't load third-party KEXTs, third-party launch agents, third-party launch daemons, third-party startup items, third-party fonts, any user login items, or any user-specific launch agents.

When deleting a local user account, OS X can archive the home folder content into a compressed disk image, leave the home folder content in the /Users folder, or delete the home folder content. Optionally, OS X can perform a secure erase on the home folder content.

The Font Book application shows a small dot next to the name of any font that has duplicate resources.