You can point to a missed tackle here, or the third-down run there, the fact of the matter is that they all stacked up in the Chicago Bears defeat of themselves.
Yes, while Brock Osweiler played better than expected, and the Miami Dolphins defense came in underrated this is a game in which the Chicago Bears beat themselves. They held an 11 point lead in the fourth quarter and a touchdown lead in the fourth. If the Chicago Bears want to be considered a contender, they have to learn how to close those games.
Think about it; they led by three scores in their loss in Week One.