For People Who Hate External Conflict
If it were up to me personally, I'd say external conflict isn't at ALL important, because what I enjoy are the characters' emotions. Their thoughts, their feelings, their inner turmoil. Who CARES about what they do in the physical world?
But it's not up to me, and millions of readers DO care what they do. And if our characters are gonna be truly plausible people, they're absolutely gonna be doing things in real life. External conflict isn't about what they think and feel, so much as it is about what they do.
Say you've got a heroine whose Internal Conflict is that she was so badly hurt by her ex-fianc? that she can never trust a man again. (Say she's moved to a new town where nobody knows the guy dumped her at the altar; otherwise her conflict is gonna include What People Think.)
So she's got an internal conflict of Inability To Trust Men. Here's good old wonderful hero, the perfect guy, except she Can't Let Herself Trust Him. All internal conflict, right?
But if all she does is sit and stew about this, the book will be dull. (I used to try having my heroine sit and stew in lots of different exciting places, hoping that would perk things up. It didn't!)
In real life, though, this heroine isn't JUST sitting and stewing. She's also driving her 98 Mazda to work each morning because her only mission in life is the job. She's coming home and feeding Miss Kitty (her only companion on lonely evenings) the expensive brand of cat food. She's explaining to her sister why she'd rather not blind-date Sis's husband's best man.
Suppose Sis doesn't believe her and the Best Man shows up at her door.
Suppose the cat-food order goes awry and the grocer says he can get her some IF she's willing to show a little, ahem, gratitude.
Suppose her car breaks down and the only person willing to give her a ride is an Untrustworthy Man.
The thing is, external conflict can come straight from everyday-life situations. It doesn't have to be imposed on the characters by some Mafia chieftain or flaming earthquake or vengeful ex-lover. If these people are living their lives in accordance with their deeply-felt beliefs (i.e. Men Are Untrustworthy), they're gonna run into trouble.
This external trouble doesn't have to last throughout the book. Your heroine could have all three of those external situations happen to her, one after another, and resolve each one in turn.
But each one is showing her more and more clearly that her internal belief is causing problems in her life.
And the arc of the book is watching how she grows and changes and learns to overcome these problems...which we romance fans know will mean accepting that the hero IS a Trustworthy Man.
Now, there are probably dozens of bestselling authors who hate external conflict and wouldn't let it anywhere near their book. And dozens more who love it and pack it into every page. But if you tend to think of external conflict as Boring or Unnecessary, try instead thinking of it as the outward manifestation of the internal conflict.
Gosh, I love that line: "External conflict is the Outward Manifestation of the Internal Conflict."
Hmm, maybe I don't hate External Conflict after all!