There are a lot of very detailed and thoughtful reviews of this movie if you want more help determining if you should watch this film. I want to talk about how to watch it. Because you should, if you can stand it. I thought some of the information on the history of the U.S. relationship with Saudi Arabia and how it affected Afghanistan to be interesting and relevant.
But, as with a few other reviewers, I felt a lot of the footage was unnecessary and distracting. We learn that things aren't always as black and white as they presented to us in news stories - that the messages have been simplified to make it easier to grasp and perhaps to hide mistakes that have been made. But in this "experimental" documentary, the explanations are muddied with clips that perhaps are designed to make us think, but in my case a lot of my thoughts were, "What is the point of this?"
"Bitter Lake" could be an important movie if it were a lean 80 or 90 minutes long instead of 2 1/4 hours.
But if you try watching and find yourself losing patience at times as I did, or if you are hesitant to even start watching, I have a suggestion. Watch the screen only when the narrator voice-over is present. This will give you the bulk of the orderly, historical stuff. Look away when it shifts to people dancing, or a soldier balancing a small bird in his hand. Do text messages during the comedy movie clips, or when the camera focuses for 30 solid seconds on the death stare of a "freedom" fighter. Obviously, this will be more easily achieved watching at home than in a theater, and cost a bit less, also.