I like the Best practices, for example button https://dev.office.com/fabric#/components/button

Do

Make sure the label conveys a clear purpose of the button to the user.

Button labels must describe the action the button will perform and should include a verb. Use concise, specific, self-explanatory labels, usually a single word.

Buttons should always include a noun if there is any room for interpretation about what the verb operates on.

...

Don’t

Don't use generic labels like "Ok," especially in the case of an error; errors are never "Ok."

Don’t place the default focus on a button that destroys data. Instead, place the default focus on the button that performs the "safe act" and retains the content (i.e. "Save") or cancels the action (i.e. "Cancel").

Pity that MS doesn't always follow them...