Is a Key You Already Have
Hold the Option key and click the Wi-Fi icon in your Mac's menu bar. Without opening a single app, you get the connection detail that matters during troubleshooting: the channel, the transmit rate, and the signal level, along with the PHY mode and security. For a quick read of what you are connected to, nothing on a Mac is faster. (The exact set of fields depends on your macOS version, and recent releases show fewer than older ones did.)
That one trick earns its place in muscle memory. But it is a small piece of something bigger: the Option key hides a faster version of a lot of everyday actions, and once you start reaching for it, you stop doing things the slow way. Here are the ones worth learning.
The menu bar shows more than it lets on
Option is the menu bar's hidden layer.
Option + click the Sound icon jumps straight to picking an input or output device, no trip through settings.
Option + the Apple menu turns "About This Mac" into "System Information," so full hardware detail is one click away.
Option + a volume or brightness key opens the Sound or Displays settings directly, and Shift + Option + those keys adjusts in quarter-steps when you want fine control.
Finder, faster
Command + Option + I opens the Inspector. It works like Get Info, but it updates live as you click through files, so checking a folder full of items stops being a chore.
Command + Option + Delete removes a file immediately and skips the Trash. It is permanent with no undo, so save it for the files you are certain about. Cut through window clutter
Option + click a window's yellow minimize button minimizes every window of that app at once.
Command + Option + H hides everything except the app you are working in. Option + click the green button fills the screen without dropping you into full-screen mode and its separate Space.
Move through text like you mean it
Option + Left or Right arrow moves the cursor a word at a time. Option + Up or Down jumps to the start or end of the paragraph (in most standard text fields; some editors remap it).
Add Shift to any of those to select as you go, by word or by paragraph. When something freezes
Option + Command + Escape opens Force Quit. Pick the unresponsive app, press Enter, and you are back to work without restarting.
None of these require software, a setting change, or a new habit beyond one finger on one key. If you spend your day on a Mac, the Option key is the cheapest speed you will ever buy.
Which of these were you already using, and which one are you adding tomorrow?