We’ve all been there before. Browsing Amazon at 3 AM, only to find a package of five pounds worth of chocolate-covered pretzels.

And for only six dollars! Well, let’s go ahead and order five of them so the order qualifies for free shipping.

You then wind up with stale bread covered in mediocre chocolate weighing as much as a small child, and you’re out 30 bucks you could have spent on something useful, like a DVD combo pack with all of the Rush Hour movies included at one low price. (You can throw away Rush Hour 3, or use it for cool “DVD in the microwave” science experiments.)

So what lesson can we learn from this mistake we’ve all made? (And we’ve all made it, right? Right?)

Things aren’t always as good as advertised, and less isn’t always better.

Take NFL defenses, for example. I know you’ve witnessed Sunday morning pre-game shows and heard former NFL players mail it in for a nice paycheck with quotes like “the Dallas Cowboys and their last-place defense,” or “The Houston Texans have the best defense in the NFL.”

What they mean is that those defenses have given up the most yards and the least yards, respectively, through Week 10. But in the same way that being cheap and covered in chocolate did not render those pretzels delicious and satisfying, failing to give up yards does not make a defense successful.

So you may hear claims that a certain defense is near the top or bottom of the league during a radio or television show, and buy in to this flawed logic. But don’t fear, because today we’re going to take a look at some of the most underrated defenses in the NFL.

In other words, these are the defenses that are better than advertised. Like Rush Hour 2.

“Do you understand the words that are a-coming outta my mouth?”

“Don’t nobody understand the words that are comin’ outta your mouth man.”

Comedy gold.

I’ll be evaluating these defenses using numberFire’s NEP data. If you’re new to the site or need a reminder of what NEP is, don’t worry! Head over to the glossary and it’s the very first entry in the football section.

Arizona Cardinals

The Arizona Cardinals are kind of like Rush Hour 2. If you saw Rush Hour 1 (the 2012 Cardinals) and didn’t like how it ended, you might have missed out on the greatness of Rush Hour 2.

If you don’t remember the 2012 Cardinals season, it began with four straight wins, including victories over Seattle and New England. They were riding high thanks to their smothering defense, but would eventually be let down by their horrible offense, losing 11 of their next 12 games.

There’s a similar vibe to this year’s version of the Cardinals. They have a very good defense being held back by a poor offense. In fact, using our Adjusted Net Expected Points (NEP) per play data, which takes into account strength of schedule and other factors to determine overall offensive effectiveness, the Cardinals are sixth-worst in the NFL on offense, with only the likes of the Buccaneers and Jaguars trailing them.

But the defense is a completely different story. I’ve discussed the Carolina Panthers and just how good they are; they’re the best defense in the league through Week 10 on a per play basis (second-best in total), while the Kansas City Chiefs are second-best (best in when looked at from a cumulative perspective).

In third place are the Cardinals, who feature the third-best rushing defense and the sixth-best passing defense according to numberFire’s algorithms and other mathematical wizardry.

However, you may hear someone on television say “the 13th ranked Arizona defense takes on the…” and wonder why they’re ranked so high in the numberFire universe. That is partially because they have such a stifling run defense, which ranks in the top-five in yards per game (which is a silly way to measure a defense, but the fact remains true).

But it’s also because they’ve earned 20 takeaways so far this season, and have faced a fairly tough schedule, lining up against the Saints, Seahawks, 49ers and Lions so far this year. Adjusted NEP per play takes schedule into account, so the Cardinals see a higher score for performing fairly well against tough opposition.

New England Patriots

Can’t you just hear it now?

“Tom Brady should be the MVP of the NFL, because he’s found a way to win despite having a defense ranked 21st in the NFL in yards per game. He’s doing it all without any weapons on offense, and he’s showing true grit and determination.”

The problem with that is that his defense has actually been quite good according to numberFire’s metrics, and has been bailing him out this season despite his relatively poor play. (He’s lower than Case Keenum and Andy Dalton in Passing NEP per play.)

The New England Patriots rank fourth in Adjusted NEP per play on defense, right behind the aforementioned Cardinals, Chiefs, and Panthers. This is thanks to a fifth-ranked passing defense on a per play basis, and ranking second in the AFC in takeaways behind only Kansas City.

That’s why the Patriots have been so successful this season, despite being advertised as an offensive team with Josh McDaniels telling Tom Brady what to do with a seemingly high-octane offense.

So in that way, they’re like a Scion xB. Designed to be a cool car for 20-somethings to trick out and add a bunch of speakers to, but instead they’re driven by 80-somethings who wanted a cheap car that came with cruise control as a standard option and enough room in the back for their great dane.

Baltimore Ravens

Last season, the Baltimore Ravens were a narrative waiting to happen. Ray Lewis riding off into the sunset, the emergence of “elite Joe Flacco,” and a lingering notion that the Ravens had a good defense.

The truth was that the 2012 Baltimore Ravens were the only Ravens defense since 2000 to post a positive Adjusted NEP/play on defense over the course of a season (and positive is bad for defensive NEP, guys).

In 2013, they’ve turned back to the negatives, posting an Adjusted DNEP/play that ranks sixth in the NFL, behind the Seattle Seahawks and all the teams previously mentioned. This is thanks to a smothering run defense which ranks 10th in the NFL using NEP and adjusting for strength of schedule.

The Ravens are also among the best at getting offenses off of the field on third down, as they rank fourth in the league in defensive third-down conversion percentage. This contributes to a good NEP, as they’re stopping drives and turning expected points into no points on a regular basis.

So the Baltimore offense can thank whatever power, deity, or lucky object they hold dear that they have a strong defense to cover up their awful performances so far this year, as they’re one of only 10 offenses with a negative Adjusted NEP/play.

Dallas Cowboys

It seems like I’m trying to get myself fired by mentioning the Dallas Cowboys in an article which praises defenses, doesn't it? The team that was just steamrolled by the New Orleans Saints in Week 10 should not be mentioned among the likes of the Ravens, Cardinals, and Patriots. Nor should the team that was blitzed by the Denver Broncos earlier this season, allowing 51 points and managing to waste a fantastic performance from Tony Romo. No, there’s no way the Cowboys belong in this article.

Except that they do, because they’re the 12th-best defense on a per play basis when fixed for strength of opponent, which takes into account their struggles against the two juggernaut offenses in the NFL from Denver and New Orleans.

So while you’ll hear about the Cowboys giving up the most yards in the league so far this season, and wonder if Monte Kiffin is a good defensive coach, you must be baffled that by using statistics which measure more than just raw yards and points, the Cowboys are higher than the Bears, Titans, and Browns on defense when analyzed on a per play basis.

When you look deeper into the numbers, you can see why they’d be ranked higher than last place.

Consider their game against the Philadelphia Eagles, in which they shut down Nick Foles in emphatic fashion and embarrassed Matt Barkley. And don’t forget about their Week 6 performance against Robert Griffin III, when they held the dynamic signal caller to no touchdowns and under 220 yards passing.

Remember that NEP is about more than just yards and touchdowns. It’s about the impact the defense has on the offenses’ ability to get into advantageous positions, and it adjusts to compensate for schedule difficulty.

They’ve already faced six of the top seven offenses in the NFL according to yards per game. It would be tough to find a defense which has faced a tougher slate of opponents so far this season. That gives the Cowboys a lot of leeway in their rankings, as they can only be expected to do so much against Peyton Manning, Drew Brees, Calvin Johnson and Eli Man… well, let’s just stick with the first three.

They’re also a very opportunistic defense, as only one NFL team has more takeaways this season (the Kansas City Chiefs). They’ve turned four of those takeaways into points on touchdown returns, as well. So while they might give up yards and first downs by the truckload to good offenses, they’re also capable of capitalizing on mistakes and shutting down teams that aren’t at the top of their game offensively.

Keep in mind, we're talking about what teams have done, not where teams will go. With the loss of Sean Lee, this team could be lost themselves defensively.

That makes the Cowboys like the sketchy Chinese place that you order delivery food from every week, because you’re afraid to go to the actual restaurant and witness the environment in which your food is prepared. On most nights, the food is good and you don’t get sick, so you just have to trust that the occasional negative experience is just a bump in the road, and not indicative of a flawed system.

Just like how you have to ignore Rush Hour 3, and enjoy the first two movies for what they are as works of art. Even the best actors and directors make mistakes sometimes.