The com_users and mod_login login forms only show the remember me option if the system remember me plugin is enabled. Makes it pretty inconvenient if someone opted for an alternative implementation.

(Yes, I realize most of these issues will probably never be addressed, but it highlights flaws in how core is maintained; plugins are supposed to add functionality in an anonymous way (other parts of the system shouldn't rely on a specific plugin being active to use a feature) and tying features to a specific plugin indicates the plugin is often times something that should be integrated directly into a component or there is a shortcoming in the core API somewhere else that needs to be addressed so that a plugin can add a feature in an anonymous manner)