If you’re pasting text from one application to another, it can get infuriating when the formatting from the copied text gets transported into the target document. If you copy text from an email into Word, for example–or vice versa–you can end up with clashing styles that take an unnecessary amount of time to tidy up. Extra bolds and italics where you don’t want it. Different-sized fonts.
UPDATE: There’s now a simple and free Mac app that makes this even easier. It was created by developer Sindre Sorhus, and you can find it in the Mac App Store.
MacOS also has an option for Paste and Match Style. In the vast majority of cases, that’s what I actually want to do. It’s different from the regular paste in that it takes its formatting the cue from the text you’re pasting into rather than the text you’re pasting from.
Out of the box, there are two options. You can right-click on the target document and choose Paste and Match Style from the list. Or you can use the standard keyboard shortcut Command + Option + Shift + V, which involves both remembering the combination and some digit dexterity.
But there’s a third option: overriding the default paste behavior. Here’s how you do it:
Open system preferences and choose Keyboard.

Choose the Shortcuts tab from the top. In the list at left, choose App Shortcuts. Click on the + symbol.

Set the application/s. From the Application drop-down menu, choose All Applications (or you can specify an individual application, like Mail, if you prefer).
In the Menu Title field, enter “Paste and Match Style”. Enter it exactly as is. It’s not asking you to make up a name–it’s asking you for the exact name of the existing menu command.
In the Keyboard Shortcut field, press Command + V (or whatever shortcut you want to use). That will capture the new shortcut. Command + V will override the regular paste command. You can also specify a different keyboard shortcut if you’d like to have the option of both.
Click the Add button.

You’ll then see it added to the list of available shortcuts.

Each time you use it might only save you a second or two, but those add up.
But there are, unfortunately, some instances where it doesn’t work as expected. So your mileage might vary. If you find that it’s doing some odd things, you can simply remove the shortcut by highlighting it in the list of available shortcuts and then hitting the minus button. Or you can take a more targeted approach to assign it to apply only when using specific applications rather than globally for all applications.
I’ve used this in versions up to and including Monterey.