These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Hollywood History: We're told that letting humanity off the leash led to the collapse of the Roman Empire and the Dark Ages. The fact that parts of the world outside Europe were doing just fine, or no worse than usual, during that period is ignored. Then again, this might be intentional; David calls attention to Thompson's selective focus when he treats the present like it's all good (to which he can only counter with "could be worse"), so Thompson may be deliberately emphasizing the negative.
The collapse went into the dark ages, which lead to the rise of power of the Catholic Church, which if it hadn't had happened may have went to a wholly different set of actions besides the Crusades. This is just one example. The rest of the world may have been "fine", but that doesn't mean there wasn't a large ripple effect. Think of "too big to fail" on a major scale.
One-Scene Wonder: Terence Stamp as Thompson. He is only in three or four scenes, but completely steals all of them.
Paranoia Fuel: The idea that your whole life's direction, down to what whether or not you're late for work, could be controlled by a group of cosmic beings, especially since anyone wearing a hat could be one of them.
Unfortunate Implications: In the ending, the Bureau is not gone - they just deigned to make an exception for David and Elise, and this is their happy ending. Granted, total free will would cause world wide disaster, and the moral of the story is that free will is something you earn — but are the two of them honestly going to keep on living life as usual, in a world where they know all their friends and family are following a very precise script since they haven't "earned" the right to do otherwise?
The plan is not that detailed. They admit early on they cannot possibly track everyone. They are only making him lonely and miserable, because that makes him a great POTUS. Otherwise they would not care about him.
The Bureau is not real, and living without them is what we're really doing in real life. It's going OK?