Reasoning of Donnie Darko
I'll start with my interpretation of Frank. First off, Frank the chimera should not be confused with Frank the reality. The imaginary Frank that Donnie listens to is not the teenage boy that goes for beer at the end of the movie. My interpretation is that Frank (imaginary) is a result of Donnie's collective memory. (note: For one to understand the time travel aspect of the movie, one would have to know that Donnie has traveled in time multiple times before the movie even starts. This is the reason the jet engine falls through his house at the beginning of the movie. Donnie has already played out the sequence in which he has burnt down Cunningham's home and forced his mother to take the trip with his sister's dance team, causing the engine to fall through the worm hole. :end note). I'm not sure if Donnie's collective memory is subconscious because he states that Frank saved his life. Where if he was conscious of all the events in previous sequences of time/time travel, he would have known he was about to die each time he traveled back. Donnie's collective memory may or may not be conscious, however, Frank (imaginary) can be construed as an image or icon Donnie has created to carry him through this sequence of events. Each time he starts this sequence (after he time travels) He chooses to get out of bed. Donnies final decision to end his life is the direct result of the understanding he obtains from his teacher upon discussing Roberta Sparrows book. Donnie sees these "life paths" which all humans follow. Donnie's teacher helps him to understand that if one was able to see one of these life paths, they would be able to alter it. Well Donnie can see his life path. These "life paths" are also a tangible representation of Donnies movement through life. This conversation with his teacher holds relevance to Donnie's ultimate decision to change his life path and perhaps can be seen as a defining (or at least explanatory) part of the movie. Donnie knows his life path and understands the choices he has made and will possibly make if he travels back in time to continue the sequence. He then decides to kill himself.
Part 2:
I don't know about saving the world but the affects the lives of each main character in the movie. His girlfriend Gretchen never meets Donnie, meaning she never dies. Donnie never burns down Cunninghams house, which means sparkle motion can be accompanied by Donnie's gym teacher, saving the life of Donnie's mother. Now I cant say if the plane crashes or not however I do remember Donnies mom trying to get home early, which means if she hadnt taken the girls they may have come home on a later flight, saving their lives as well. Frank never dies because Donnie is not there to kill him. Cunningham never goes to jail because Donnie doesnt burn down his home, revealing the child porn dungeon. If Drew Barrymore's character is fired after Donnie breaks the water main, her unemployment may be a direct result of the Donnie's reenactment of the book she is teaching her students (as in the school realizes this and fires her). The chinese girl is affected because she likes Donnie and now he is dead. And the psychiatrist is affected because she loses her patient. Actually this is what the ending sequence of the movie is for. Each one of those people in that sequence (from the mad world theme song on) is affected by Donnies death. So this is why Donnie choses to save himself...I can understand the whole belief in God thing, and not being afraid to die alone and perhaps that's true but everything else I've heard from you people is gargbage so read this, put it in your pipe, and smoke it.
Part 2:
I don't know about saving the world but the affects the lives of each main character in the movie. His girlfriend Gretchen never meets Donnie, meaning she never dies. Donnie never burns down Cunninghams house, which means sparkle motion can be accompanied by Donnie's gym teacher, saving the life of Donnie's mother. Now I cant say if the plane crashes or not however I do remember Donnies mom trying to get home early, which means if she hadnt taken the girls they may have come home on a later flight, saving their lives as well. Frank never dies because Donnie is not there to kill him. Cunningham never goes to jail because Donnie doesnt burn down his home, revealing the child porn dungeon. If Drew Barrymore's character is fired after Donnie breaks the water main, her unemployment may be a direct result of the Donnie's reenactment of the book she is teaching her students (as in the school realizes this and fires her). The chinese girl is affected because she likes Donnie and now he is dead. And the psychiatrist is affected because she loses her patient. Actually this is what the ending sequence of the movie is for. Each one of those people in that sequence (from the mad world theme song on) is affected by Donnies death. So this is why Donnie choses to save himself...I can understand the whole belief in God thing, and not being afraid to die alone and perhaps that's true but everything else I've heard from you people is gargbage so read this, put it in your pipe, and smoke it.