Even if in real life things happen by chance, in fiction, everything happens for a reason and makes sense.
This means that if something happens randomly, the reader gets bored and/or annoyed.
The more imaginative the world you create, the more logical and credible it has to be, otherwise you will not be able to make it credible enough for your readers.
In fiction, nothing happens for no apparent reason.
What makes a lie believable? It is believable because it makes sense. Same for your world; it is believable because everything in it makes sense. And authors have been called good liars. Good liars always try to concoct a story that makes sense. Although the truth does not have to come with an explanation or a manual, a lie or a make-up world does.
Also, your heroes skills cannot be random. They need to come with the right qualifications to tackle a task.
And the hero needs a logical motivation to do what he or she does. He cannot take a plane out of the blue, but needs a solid reason to do so.
For each cause there is a reaction in fiction.
Your character cannot pass on anything that is happening around him. If something happens, someone will react to it and there will be consequences.
If your hero is looking for a job, the job will be part of the main plot. Finding a job will be at the heart of the plot or finding the right job for your hero will be the main problem of the story.
If your hero steps into a shop, it’s because she is going to get married soon and the bridal dress is an important part of the plot, or your heroine is a shopaholic and that’s the main problem of your novel.
If your hero walks into an office, then you need to have someone who invites her in.
If your hero goes to eat lunch, then you need to explain that he has a meeting with someone there.
In real life, we can opt to take another road to go to work, but not in fiction. In fiction, if the hero changes his routine, it’s because he has a strong reason to do so. The reader expects something unusual to happen or expects the hero to look for someone or something there.
In fiction, if the heroine breaks the heel of her stiletto, it’s because someone pushed her over a manhole and the heel got caught in the lid’s hole. Actually, if the heroine is wearing stiletto is for a reason and if she walks on that path it is for a reason too. In fact, if she breaks the heel of her stiletto it’s because you need this to happen for her to discover a clue, meet someone, or make something else happen.
And so there is this chain of events that never stops.
Like a domino line.
In fiction, for each action, there is another action (a stimulus) and for each motivation there is an action.
And you cannot have a hero responding to a thought or feeling. Your hero needs to react to an external action/stimuli.
Catherine Brady's Story Logic and the Craft of Fiction