Source: Auremar/Shutterstock

I've been studying apologies—and the people who can't give them—for more than two decades. But you don't need to be an expert on the subject to recognize when a bad apology flattens you.

Here’s a list of the nine essential ingredients of a true apology. The next time you need to offer an apology—or are on the receiving end of an apology that doesn't cut it—remember these guidelines.