My fellow author Christian aka Leo King posted another one of his little video blogs about building sympathy for your characters. This time around he discusses the "everyman moment", where you put your character in a situation that inspires the reader to say "I'd do that if I was them." I like this idea, although I propose an extension to how it's to be approached.
When we say "I'd do that if I was them," this seems like something that needs to be presaged by inspiring another sentiment on the part of the audience: "It makes sense that they would do that."
I come back to Anne Tyler's The Accidental Tourist a lot because it's such a great example of the author building empathy in the audience for a character who needs and deserves it. Macon Leary, the sad-sack protagonist who writes travel books for businesspeople who hate traveling, has a lot of "I'd do that, too" moments, but they only become that way because they are really "it makes sense he did that" moments.
We come to understand that Macon is this way because of certain things in his life — his ongoing divorce, the senseless death of his son, the baggy aimlessness of his job, the emotionally stunted upbringing he experienced — and as those details are filled in, his behavior acquires more and more context, more weight. What he does makes sense in the light of who he is.
This includes things that, outwardly, shoudn't make sense. At one point Macon goes to New York City and has a panic attack in a tall building. In a lesser book, it would come off as melodramatic. Here, it's one of the logical consequences of what has been put into him up to that point, and his general inability to deal with it. It makes sense that he freaks out like that, and if I had lived that emotionally parched a life, I'd do that too. With this context, the scene in the book becomes more than just a record of twitchy behavior.
I think what Leo is talking about with an "everyman moment" is something that should come as a culmination of other things. It seems to work best when used to cap off, to put into greater context, the character we have been building — to make us say "I'd do that" because by that point we haven't been given much of a choice except to feel that way.