1. Browns might have had too much rest in Week 18
When Cleveland won their fourth game in a row with Joe Flacco under center — which was on Thursday Night Football against his old team, the New York Jets — it locked up their spot in the playoffs. By the time the rest of the games were done that weekend, the Browns knew they would be the fifth seed. Their final opponent, the Cincinnati Bengals, were also eliminated, meaning Week 18 wasn't going to impact the standings.
Cleveland responded by resting the majority of their starters, including Flacco who had been on an absolute tear. The move made sense for players such as Amari Cooper and Elijah Moore, who were coming off injuries, but perhaps they should have put Flacco and the rest of the healthy starters out there for at least the first half.
By sitting them, it meant their final game of the season was on December 28 and they didn't play again until January 13. That time off could have helped with the aforementioned injuries but it also seemed to wipe out a lot of the momentum their offense had as they lost 45-14 against the Texans (and 14 of the points Houston scored came via interceptions).
Again, it seemed to be the right move to rest their players but with hindsight being 20/20, it would have been better to allow their starters to get some time on the field and keep their momentum going. The good news is that this roster is talented enough to get back to the playoffs but they should try and learn from these three mistakes as they look to take their next step.