I'm going to say it...I'm not a fan of the flashback. The word reminds me of cheesy thriller or mystery novels that involve stereotyped 1970-1980 detectives. Or the ex-cop facing off against the criminal who killed his wife and kid in revenge (overused plot alert).
Merriam describes a flashback as "an interruption of the chronological sequence (as of a film or literary work) of an event of earlier occurrence". This is probably why I don't like them. They are really just a mechanism for an info dump and I don't like info dumps. I want the information to flow out during the course of the story.
In my reading adventures - and I am a reader of vast material - info dumps side track you from the point and make it difficult to follow the storyline or keep engaged with the characters.
I know the pro argument for flashbacks. They provide pertinent information to the current situation, including character motivation, relationship dynamics, and conflict. My response is always, "Maybe you're starting the story at the wrong place then". Or maybe you're putting too much into the "pertinent information".
Now if there's parts of the characters "past life" (pre-novel) that is important, you can work those concepts in to the current storyline by their reaction to certain situations and dialogue. Take Under the Dome by Stephen King, since I just did the review and all. He worked the character's past life into the modern story without info dumping or flashback scenes. He did it with tasteful glimpses through thoughts and conversations in the moment.
Well, imagine my surprise when I realized that my Galileo dream sequences were actually flashbacks? Groan and curse...dang it! Then imagine my chagrin when I realized that my like of dream sequences have faded the more I learn my writing style.
Now dream sequences I've seen done really well in regards to the characters internal conflict and foreshadowing events to come. I just don't think that I am the kind of writer to do them well and all mine reference past events and relationships.
Now I have these ugly things in my story and I have to find a way to work the core point of the content in better ways.
Time to be a dream killer...good writing all!