First thought, for "About This Mac" I usually want the model number and serial number.

Second thought, is it fashionable now to not include a "Cancel" button in settings dialogs?

Many times, I have navigated all of the pages of a settings dialog to change a setting or multiple settings, then realise I liked it better how it was before, and have no idea what the settings were before I changed them.

Just yesterday I wanted to try a new theme in Xfce - change the theme, not happy with it, and no idea out of the 50 themes what it was before I changed it, so now I have to go through every option to find the one that was (approximately?) what it was before.