It's good because if your writing is not active, it's passive and passive is bad. Passive voice tends to distance and is more formal. Often, it weakens a sentence by using more words than necessary. More words than necessary is bad because the reader needs more time and effort to process a sentence and form a picture. This violates Carolyn's First Rule of Writing: Fiction should be active and immediate.
With passive voice, the subject gets the action, as in the infamous sentence, "The boy was bitten by the dog."
There are many ways to make your writing more active. Rooting out the passive is only one (important) way. Here's example number One:
Not active (31 words) Not active parts in yellow
Geneva was walking toward the well. She had been dreaming of it every night. Big green plants were growing all over the pumphouse and had for years been covering the door.
active (22 words)
Geneva walked toward the well. She dreamed of it every night. Big green plants grew over the pumphouse and covered the door.
What about Backstory?
Just about every novel has a certain amount of backstory that needs to be conveyed. Ah, you say, but it's backstory and happened in the past. How, then, do you avoid the passive voice?
By working at it. Let's say your heroine's parents are dead. How do you convey this to your readers? Note: these examples assume the backstory being related is, in fact, crucial to your story. (See Carolyn's Second Rule of Writing: Don't tell readers stuff they don't need to know.)
Backstory That isn't Active and Immediate
Geneva's parents were dead.
Active Backstory
Geneva's parents died in a carriage accident.
How about a more complicated example? Your heroine's parents are not only dead, but they died when she was only six, and she was riding in the carriage when it happened, leaving her with a lifelong guilt because she climbed out and was unable to extricate her parents from the wreckage.
Backstory That isn't Active and Immediate
Her parents were killed in a carriage accident when she was six. She was sitting on her mama's lap when the carriage turned a corner and tipped over. She could hear the screams of the horses as she was crawling from the wreckage. She'd turned and grabbed her mother's hand. She had called and called for her mother and father to come out. But they hadn't.
Active Backstory
The same nightmare awoke her every night. Mama, holding her tightly, always told her, "Such a big girl you are now. Six years old! Why, you hardly fit on my lap."
"Our little girl will be married before we know it." Papa laughed from the driver's seat. His laughter turned abruptly to a shout. The horses screamed shrilly. Wood shattered in one booming, deafening descent into chaos and darkness. A faint light showed Geneva freedom, and she crawled toward it. There, on the ground, she called for Mama and Papa. They never answered, and the nightmare never varied.
The second example is not completely in-active, which is good. But it uses more words. Is that bad? Not in this case because the passage also conveys more information than the first, and it does it without telling. Here's what a reader might deduce: her parents loved her. Her father liked to laugh. Her mother and father had a happy relationship. The heroine is haunted by this event. The first passage isn't anywhere near as evocative.
Your assignment
Take a look at Chapter 1 of your work-in-progress (WIP). Eliminate forms of the verb "to be" wherever you can.
Extra Credit
Find a place where you're conveying backstory. Rewrite the passage so that it's active.