I did not know holding option in a right click menu had so many useful features!
Also, on command clicking the title bar to go a folder above: my memory is probably failing me but I seem to recall when this was announced there was an arrow or some such, or highlighting.
It works on almost any menu; not just right click context menu. XCode for example, is much more useful when you realize you learn that half of the menu options you really want are hidden by holding down the option key.
The WiFi icon has an insane amount of information if you option click it for example... (most of the system ones do)
Holding option in menus, settings, or while clicking the status bar is easily the most underused and under-documented feature of MacOS... (maybe after removing annoying shit with launchctrl).
Edit: totally didn't see the two other posts with exactly the same tip, ha. Maybe not so underused -_-;
On command clickng the window title: this feature has been around since classic Mac OS (I believe, it had been introduced in one of the many iterations of System 7) – there was definitely no indicator or hint. But the functionality was about the same as the location drop-down at top center of the file dialogs and was anchored in about the same position. It may have been one of the first hidden features, apart from the easter egg in the Finder's about box.
Holding option and clicking on a lot of things will unlock advanced entries. For instance, hold option and click your WiFi button in the top menubar to see advanced WiFi stats like channel, speed, etc... same goes for Bluetooth device menu and others.
Nice! I have used MacOS for years and had no idea that this exists. Tooltips would be perfect use for this. Hover over the Wifi icon and the tooltip tells you that option will show you more.
Also, on command clicking the title bar to go a folder above: my memory is probably failing me but I seem to recall when this was announced there was an arrow or some such, or highlighting.