My two-year old’s new favorite word is “why?”

Whether it’s questioning the reason behind my desire for him to eat dinner or demanding an explanation for that regular onset of darkness we like to call “night,” his response is the same: why?

Why, why, why, why, why?

Needless to say, I’ve had that question on my mind quite a bit recently. As writers, “why” is one of the most important questions we need to answer. Specifically, why do our characters act the way they do? Why do they make the choices we need them to make to propel the story? When the logical thing to do is A, why do they do B instead?

Good stories are made from characters doing B when they should have done A. However, good stories are ruined when the author doesn’t show why the character chose B. If you don’t have a believable why, your whole story falls apart. Readers will believe just about anything within the context of a story as long as it makes sense. Once you stop making sense, once you lose your reader’s belief, you run a very real risk of losing your readers completely.

Sometimes, that why – the character’s motivation – is pretty obvious. Your character is being chased by a pair of hired thugs, so breaking into the nearest house to hide is a reasonable action. It would be equally reasonable if your character was a thief in search of expensive jewelry or electronics that she knew were in the house. The desire to protect oneself or gain wealth are motivations most people have experienced. They’re easy to relate to, which in turn makes them easy to believe when other people act on them.

Sometimes, unfortunately, that motivation isn’t obvious at all. That usually happens when you’re hit with inspiration. A fascinating, hilarious, or emotionally powerful scene unfolds in your mind. If only you had some idea how the characters got in that situation in the first place….

What do you do when inspiration strikes but doesn’t bother to explain itself? By looking at three factors, you can create believable motivations that explain why the characters are in the situation you want them in.

Let’s say you’re writing a romance and you want your main characters to meet when your heroine, normally a straight-laced librarian, breaks into the home of your hero, a newspaper reporter? How are you going to sell that to your readers?

The first factor to look at is basic human psychology. People will usually try to protect and preserve what is important to them. Beyond that, they’ll usually find a way to do what they truly want to do, even if they don’t know they want it.

Let’s start with that. What might your librarian be trying to protect?

Unless your librarian has a secret life as a cat burglar, she’s probably not in the habit of breaking into people’s houses. In fact, she probably has moral standards that tell her breaking into a place is wrong. As the author, you can’t just have her breaking in because you want that scene in the book (no matter how good a scene it is). She’s going to need a strong reason to overcome her morals and habits. For instance, she might be the person from above who was being chased by hired thugs. She might have reason to believe the news reporter has some racy pictures of her that would cause her to lose her job.

In both of those cases, her need to protect herself (her life, her job) gives her a strong reason to do something she normally wouldn’t do.

The second factor is your specific character’s personality. If your librarian is a free-spirited type who doesn’t care what other people think, she’s unlikely to worry much about racy photos. On the other hand, she might be more likely to break into the reporter’s house to help out a friend who needs the racy photos to disappear without a trace but is too scared to try to get them herself.

The third factor is how well you sell the first two factors. You have to show your character’s reasoning and the emotions that color their reasons.

If your librarian is running for her life, she’s probably terrified and desperate. She’s looking for any safe place. She might have a moment of doubt about breaking in, but she’s not going to stand around for an hour debating the ethics of it with herself.

If your librarian wants her racy photos back, there’s got to be some reason why she thinks those photos being published would be worse than breaking in to someone’s house. Losing her job is good motivation, as long as you show your readers her fears that she won’t be able to get another job, that she won’t be able to support herself or her family, that she’ll do anything to avoid embarrassment and ridicule.

If your librarian is helping a friend. you have to show the strength of that friendship. You also have to show that your librarian has a daredevil attitude and doesn’t mind ignoring society’s moral standards if it means helping a friend.

In short, you can make almost any motivation believable if it fits in the spectrum of normal human behavior and your character’s specific personality. The key is to lead your reader through the thoughts and emotions that create your character’s motivation. When you do this, you’ll have your “why” – and most likely, a page-turning story that keeps your readers up at night trying to find out what happens next.