It's always an excellent excuse.

You know you're selling something that's me-too, been-there, done-that, so-the-same.

You decide the best way to differentiate it is to get a celebrity to endorse it.

I know this is just run-of-the-mill-from-a-really-second-rate-mill toilet paper, but if we could just get Rihanna to say it's great, we'll make mill-ions.

Naturally, things don't always work out that way. Or even often.

Hollywood itself knows that just because a movie's got stars in it, this doesn't mean that people will flock to see it.

How did Disney's "Tomorrowland" do in its first weekend? Not so well, despite starring George Clooney.

Still, Hollywood and brands continue to believe in fame.

So, given that they're not going to change, perhaps it's best to see which famous faces are the best salespeople. To this end, Nielsen decided to ask real people.

Nielsen surely knows that real people tell the truth even less often than stars in movies, but still.

The conclusion of this stunning Nielsen research is that Liam Neeson is the man you need to front your brand. At least right now.

The survey covered the last three months of ads. It measured such nebulous concepts as likability, influence, public awareness and Glock proficiency. (I made that last one up.)

Neeson beat out everyone but Pierce Brosnan. However, Nielsen decided that ultimately Neeson had more sales influence among consumers. His was, at heart, the most meaningful N-score. (If you're going to tell people that you know who the winner is, you'd better brand the score.)

I'm sure you're sitting there right now, telling yourself that you know which products Neeson has been advertising lately.

They're just on the tip of your forehead, but you can't see the words. The name of the brand is being formed right now in your mouth, yet it won't emerge. It's annoying, isn't it?

Please let me help you. Neeson appeared in Super Bowl ad for "Clash Of Clans."

In it, he threatened a fellow gamer called BigBuffetBoy85. Well, that's (likely) not his real name.

Being threatening is a Neeson thing. He's well-known for righteous intimidation in the "Taken" movies.

How can one not conclude, therefore, that in order to be the perfect pitchman, you need to have that threatening flavor -- and I don't mean that of some brands of organic yoghurt in your local Whole Foods?

Selling, perhaps, involves just a touch of intimidation. Brosnan himself is someone who oozes charm, but bruises human beings -- well, except in "Mamma Mia!"

Another very popular pitchman, if you buy this N-score thing, is Matthew McConaughey.

Surely you've seen his ads for Lincoln. Surely you've rushed out to buy one. Quite a lot of people did, so Lincoln says. This despite McConaughey in these ads covertly suggesting that a little ganja can go a long way toward uttering spontaneous gibberish.

So McConaughey isn't menacing, you'll tell me. But wait. His most recent star turn was in "True Detective" where he wielded a gun with purpose, as well as philosophy with Woody Harrelson.

I can only, therefore, reach one conclusion: people want to feel a touch of implied intimidation from the person selling to them. This is my Menace Theory.

You'd think it might matter whether your ad actually has an idea behind it. Perhaps it doesn't matter very much. It matters who utters the sales pitch. It matters if they're capable of mean.

Ultimately, if you believe these N-scores, TV watchers like it when the man selling them something has the ability to fly off the handle if you don't do what he says.

This is a marvelous revelation. Indeed, I see on the Nielsen list is also J.K. Simmons, who won an Oscar for beating a nice young man who only wanted to play the drums.

My Menace Theory doesn't explain the appearance of Jennifer Garner, Natalie Portman and Sofia Vergara on the list. Or does it? You surely don't want to mess with any of them.

This needs to be analyzed further. Why are humans currently so moved by the promise of a menacing mien? Is it the tenor of our uncertain times? Is it our need for brands to simply be better, stronger than us?

Unless, of course, people are just telling the researchers which actors they currently like. That would be a terrible waste of research, wouldn't it?