Back in April, before the NFL draft, we had Ezekiel Elliott in studio in Bristol for a day. When athletes come in, we give them a lot to do, and one of Elliott's tasks was to do his own projected first-round draft order -- or top five or 10, something like that. And he filled every slot with an Ohio State player (which wasn't as far off as you might think), but it struck me that he didn't list himself first.

Instead, he went with offensive lineman Taylor Decker at No. 1.

"The slobs, man," he explained when I asked. "I gotta take care of my slobs."

It wouldn't be long before Elliott met a new group of "slobs" and made beautiful music with them. Elliott led the NFL in rushing by a margin of 318 yards, running behind a Dallas Cowboys offensive line loaded with fellow first-round picks. Elliott is a special player, worthy of the No. 4 overall pick Dallas used on him in April, but there's little doubt that he and the league's best line got the most out of each other in 2016 as the Cowboys rolled to a 13-3 record and the No. 1 seed in the NFC playoffs.

There's also little doubt that the Oakland Raiders' 12-4 record has a lot to do with their monstrously large offensive line -- a group that elevated to a new level thanks to the offseason signing of Kelechi Osemele. The New England Patriots' offensive line was their Achilles' heel in last year's playoffs, but this time around, it's one of their strengths. And if you want to know the big difference between the Atlanta Falcons' 8-8 record in 2015 and their 11-5 record this season, you don't have to look much further than their offseason signing of Alex Mack to stabilize their line.

The Miami Dolphins made the playoffs because their line came together at the right time. The Seattle Seahawks limped to the finish line because its never did. Playoff hopefuls like the Cardinals, Broncos and Bengals couldn't overcome poor offensive-line play. Tennessee arrived as a surprise contender in large part because of the performance of its recent first-round linemen.

So, as we look back on "what we learned" for one final time this season, it might not strike you as any huge revelation that success in the NFL depends on offensive-line play. But 2016 surely reminded us, if we didn't know already, of the importance of the big fellows up front to whom the likely offensive rookie of the year refers to as "the slobs."

Here are a few other things we learned -- or had reinforced -- in 2016:

Coaches are going to keep trending younger

The two youngest head coaches hired in last year's cycle -- 39-year-old Ben McAdoo of the New York Giants and 38-year-old Adam Gase of the Dolphins -- are in the playoffs as rookies. So when you start hearing the finalists for this year's openings, don't be surprised when they include the likes of 40-year-old Josh McDaniels in New England, 37-year-old Kyle Shanahan in Atlanta and even 30-year-old Washington offensive coordinator Sean McVay. All of those guys are already fielding interview requests. McDaniels and Shanahan could even be the most likely coordinators in the whole league to land head coaching jobs this cycle.

Given that Gase and McAdoo got those jobs last year, teams obviously aren't afraid to hire young. But if either (or both) of those guys would have looked overwhelmed in their first year, you might have seen some apprehension creep in. McAdoo and Gase did the likes of Shanahan and McVay a solid.

Ben McAdoo led the Giants to an 11-5 record and a playoff berth in his first season at the helm in New York. Brad Penner/USA TODAY Sports

Bill Belichick is better at his job than anyone has ever been

He went 3-1 in the first four games with Tom Brady suspended and his backup getting hurt in the second game. He traded two of his best defensive players -- one in the offseason and one during the season -- and his team still allowed a league-low 15.6 points per game. And you can tell me they didn't play anybody, and you might be right. But who besides maybe Pittsburgh are they going to play in the AFC playoffs whose offense scares you? Belichick is the best at identifying the situation and how to succeed within it. If the Patriots' schedule gave him a chance to tinker with the defense on the fly so it would be at its best for this time of year, then good for him for acting accordingly.

No one should be in a hurry to trade their backup quarterback

Yes, I know the one in Dallas makes too much money to be a backup, and I know the one in New England could probably start somewhere else. But Matt McGloin, Matt Cassel, Tom Savage, Matt Moore and Matt Barkley were all starting games at the end of the season. Quarterbacks get hurt, and there's no way to know where or when it'll happen. If you have a backup you like and know can win, you'd better charge an awfully steep price if you're going to trade him. The Raiders' beautiful season could have but one game left in it because their quarterback broke his fibula in Week 16.

With Derek Carr (right) out with a broken right leg, the Raiders will have to turn to backups Connor Cook (left) or Matt McGloin for their wild-card matchup at Houston this weekend. Kelley L Cox/USA TODAY Sports

There's more work to do on this game

The NFL has work to do on head injuries, the policing of head shots during games, the manner in which games are officiated and the way replays are handled, the marketing of its best players, the strictures of its anti-celebration rules and ... lots of stuff. The owners' offseason focus will, as usual, be on beyond-the-field issues like franchise relocations, stadium financing, expansion of international plans and, yes, trying to get the players' union to agree to extend the CBA. But significant attention needs to be paid to the on-field product, and perhaps all the hubbub about sinking TV ratings will help them realize that.

Solutions exist. Hits to the head can be made reviewable. Officials in New York can help on-field officials adjudicate games more easily in real time. And for goodness' sake, players should be able to wear different designs on their cleats if they want to wear them. But the NFL should spend its offseason focusing internally rather than externally, because you don't want to spend all your time thinking about how to market your product elsewhere only to turn around and find that it's become less marketable in the meantime.

That said, it sure can be fun

David Johnson, Drew Brees, Von Miller, Marcus Mariota, Mike Evans ... these are just a very, very few of the brilliant stars who entertained us all season and won't be playing in the playoffs. Lorenzo Alexander's 12.5-sack season after a long career as a special teamer and backup linebacker was one of my favorite stories of the year. The NFL can be ugly and violent, but it can also be breathtaking ballet. As fans and observers, it's understandable to struggle with the dark side of it all while also enjoying the beauty.

I'm very much looking forward to seeing whether the Cowboys' rookies can cash this in, whether Aaron Rodgers can keep running the table, whether the Giants can really win it with defense and what it'll take for people to notice the Falcons. I'm eager to see whether the Raiders can fight out of their quarterback crater, whether the Steelers' stars can light up January, whether this is really Andy Reid's year, whether anyone can stop Tom Brady and the Patriots. And while I know we'll get too bogged down in officiating and controversy and which players we're supposed to like and not like, I'm going to keep looking for the good stuff and enjoying it when I find it. It's a new year, after all. What's the harm in hoping for the best?