Every dog has his day (Detroit is still waiting) in the NFL, but there is a general consistency this season all the same. This includes the norm that bad teams repeatedly show why they lose, even if now and again they have a good day.
The Giants were beat by the generally bad Browns, who are one of those mediocre teams that show up around once a month, and the Jets showed that even the lowly Raiders can take advantage of bad play (though not versus the Panthers). The Giants seemed almost happy to have that one loss, getting it out of the way, though the Titans don't seem to be too stressed by their surprisingly consistent play. And, some teams can surprise -- see Falcons -- by such consistent play, part of that much talked about "parity" that is not a bad thing.
Bad or flawed teams lose, even when they see ready to win. Consider the SNF game, Giants/Eagles, Vice President Elect Joe Biden watching in the wings. The Giants in effect gave the Eagles a chance to win, including by an ill-advised (stupid) attempt to jump over a player to get extra yardage. But, when the Eagles was driving near the end of the game, down by 5 (their defense held the Giants back to keep it close), they could not get a necessary yard. One team was able to go for two near the end of regulation to beat a bad team; two bad teams could not get that two in order to win or tie.
And, in a pretty good MNF game, down to the final last minute drive, another bad team (the NFC West is horrible) could not score from the 1.