Reset to defaults wherever possible

simply put defaults button on some settings where critical changes could destroy or difficult to reset.some times changes are unwanted later so RESET TO DEFAULT would be great.custom changes can be set back to factory defaults i.t when system was installed,some settings when made custom changes like setting path to icon or changing an icon there is no way to go back to default setting that was set when i installed that application.so "reset to default" would help to go back to default settings.like
when changing "settings" of system add Defaults button
in "appearance" settings reset to default button or default button.
in Network settings
in screen resolution
in power management
i cant think of more now but surely others too need this setting.