Similarities between Vonnegut and O'Brien

The similarities between Vonnegut and O'Brien's writing styles are easy to navigate. They both start off talking about one thing and almost immidiately after the reader get set into one story, both of these writers begin to go off on a tagent or reflect on a whole different story than the one they are currently telling. These stories are usually flashbacks and both of these authors writing styles are disorganized and neither of these stories follow a time lineage because they refer back in time so many times. Another very important similarity I noticed in both of the writings is the use of metafiction. Metafiction is a type of writing style that self-conciously draws attention to the actual writing and the author questions his/her self if what they are writing is actually real or not. And this guessing is actually written in the actual story while the author is trying to tell another story. Vonnegut and O'Brien force the reader to question their creditability. O'Brien is constantly giving different definitions of what a true war story is and is doubting his own memory of the event of Lemon getting killed in his story itself and Vonnegut has a character that believes in aliens and can time travel. It's almost like they want you to question their creditability while they themselves question their own creditability. I also believe Vonnegut and O'Brien suffer from PTSD and their writing cleary shows it because they relive moments from a long time ago and their brains are very scattered. 
Another interesting aspect of both of these writers is their use of dark humor. The use of dark humor by both of these authors also shows their coping mechanisms with what happened to them many years ago. By viewing past situations in a funny/humorous way it helps distract the authors from the actual scary event that did happen. For example, this was shown in O'Brien's text when the guy was singing while picking up Lemon's blown up body parts and is also shown in Vonnegut's book when Billy tells the story of his dad teaching him how to swim simply by throwing Billy in the water. It's just a humorous way to deal with the pain and to get their minds off of the tragic events that happened.