Some of the most dismally wrongheaded performances I have ever seen have been wedding toasts — and I used to review off-off-Broadway theater.

There was the groomsman who made the toast all about himself and the bridesmaid whose anecdote about the married couple’s first date included the bride’s first impression about the groom’s appearance that was too harsh to be laughed off. So many hack advice dispensers (“Never go to bed angry”) and generic chin strokers (“Was it Shakespeare who said …”).

Bad toasts have become a popular comic trope in movies and TV and sketch shows like “Saturday Night Live.” Catastrophic ones provide reliable laughs in cringe comedy. Think of Steve Buscemi’s drunken, resentment-filled best man toast in “The Wedding Singer.”

But as a critic who appreciates a big swing, I’d like to come to the defense of one of the most demonized comic forms: the risky toast.

The common fear of public speaking is the core of the new book “How to Write a Funny Speech … for a Wedding, Bar Mitzvah, Graduation & Every Other Event You Didn’t Want to Go to in the First Place,” an inspired piece of service journalism by comedians Carol Leifer and Rick Mitchell.

Mitchell, a stand-up and Emmy-winning producer, and Leifer, a comic who has written for “Saturday Night Live,” “Hacks” and “Seinfeld,” are seasoned professionals. Leifer is an especially accomplished and respected veteran and has worked on many award shows, especially the material written for celebrities to present awards. This is tricky work requiring diplomacy and comic chops, exactly what you need to figure out the right thing to say at your aunt’s third wedding.

Their book takes the reader by the hand, offering reassuring words and simple, direct and practical advice: Do not go over five minutes. Avoid platitudes and cursing.

Alternating between a comedy guide, with pointers on how to think about your speech, and a joke book, the text is filled with lists of one-liners to use and also to steer clear from. (“It’s nice to see he married outside the family this time” is one example.) There are even mad lib-style structures for retirement party or bar mitzvah speeches, where you can just fill in the blanks and use them.

The most interesting pages reprint speeches by the authors with their notes in the margins, adding punch-ups, even disagreements. It’s like eavesdropping on smart comedians talking shop.

But as is the case with even the most successful how-to books in creative fields, the focus is on the good enough, not the great. Part of this is the inevitable result of boiling things down for a large audience. But there’s a broader tentativeness here that reflects a cultural paranoia about flubbing a toast.

The reality about bad toasts is that most of them are not disasters, just merely forgettable. And the best ones are a little messy. They are overly emotional and show off personality. They tend to be specific, have a point and tell the crowd something they didn’t know. Or they are just entertaining because of a certain swagger.

The greatest father of the bride toast that I ever saw had a cocksure attitude, was flamboyantly full of love and ended with an actual mic drop.

I am partial to speeches that mention elephants in the room or that tiptoe close enough to inappropriate to get people worried. And just in case you think I don’t practice what I preach, I once gave a wedding toast that told a story about visiting the groom in Moscow and ending up at a restaurant neighboring a brothel. This anecdote featured Russian prostitutes, broken glass and some moderately salacious conversation. It could have gone terribly wrong. Bringing up a story about a brothel at a wedding creates tension in the room. Grandparents sit up in their seats, look around and wonder: Where’s this going? The benefit of this anxiety is that if you make it through the story without hitting any trip wires, the release of it produces laughter that no joke book can.

It’s partly why the most popular brand of best man or maid of honor toast is the gentle roast. The best man leans on personal stories to insult and haze the groom he knows well, then gushes vaguely about the bride he doesn’t.

The goal here is making the target cringe, but not too much. But not too little. That’s not just because a speech benefits from drama. It’s also that the more you tease, the more likely you are to get a laugh. Roasting gives you credibility when you pivot to a more emotional sentiment.

Funny, funny, schmaltz. That’s the classic structure of a wedding toast. People always say that comedy is harder than tragedy, but with toasts, the schmaltz is just as tough to get right. The key is to understand that the two are inextricably linked.