The shortcuts worth memorizing, Windows and Mac side by side, searchable by key, action or app.
Shortcut fluency is a compounding skill: the ten minutes spent learning Ctrl+Shift+T (reopen closed tab) or Win+Shift+S (region screenshot) repay themselves weekly for years. This directory keeps the high-value set, around ninety shortcuts across system, browsers, text editing, spreadsheets, email, terminals and code editors, in one searchable table with the Windows and Mac versions aligned, because the translation between platforms (Ctrl becomes Cmd, Alt becomes Option, and a handful simply do not exist on one side) is where switchers lose the most time.
Learning advice from heavy users: do not study the table. Pick three shortcuts for the app you live in, use only them for a week, covering the mouse with a towel is the classic trick, then add three more. The directory's search is the reference; your hands are the student. App-specific depths (Excel's hundreds, VS Code's hundreds) live in each app's own shortcut settings, searchable there with Ctrl+K Ctrl+S in VS Code's case, the one meta-shortcut worth learning first.
Why do some Mac cells show a dash? That function does not exist or has no default shortcut on macOS (File Explorer is the obvious one). The honest dash beats an invented equivalent.
What is the single most valuable shortcut here? Reopen closed tab (Ctrl/Cmd+Shift+T) for browsers and undo (Ctrl/Cmd+Z) everywhere else, the two that undo the two most common daily accidents.
Can I change shortcuts I dislike? Both operating systems allow remapping many system shortcuts (Windows via PowerToys, macOS in Keyboard settings), and most serious apps expose their full map in settings.