Trekking further along the editing tracks, let’s take that gander at reaction.
We know actions assist in character portrayals. The things a character does reveals something about his/her nature. For example, if Lester taps the table frequently, it shows he’s nervous or deep in thought or impatient; we’d need to provide more detail or actions to convey precisely what Lester is experiencing and/or thinking. If Jenny slaps a wall, it’s possible she’s angry or has remembered something important. Actions can (should) disclose elements of someone’s personality.
The same holds true of reactions. How a character reacts or responds to an action or comment, event or situation, discloses something about his/her disposition. Readers learn what makes a character tick, what sets him/her off. If Chelsea screams at Josh after Josh knocks over a cup of coffee, it could suggest she angers quickly, she’s impatient, or she’s irrational. Additional details, such as what transpired before or after, would provide more insight.
Characters’ reactions can affect emotions. If Cecilia is upset with best friend Lidia because she didn’t show up at Cecilia’s 30th birthday party, we might feel for Cecilia—first, because Cecilia was counting on her best friend to attend this milestone celebration and second, because it saddened her. We might even become angry with Lidia for being so uncaring. How readers react depends on how various components—characters, dialogs, actions, reactions, and scenes—are shaped.
Which work(s) better?
♦ Ralph flipped back the blanket and rose, standing on unsteady feet as a sense of trepidation washed over him. He grabbed his sweater and put it on, and rushed to the basement door. He found the doorknob hard to turn, but when he heard the scream again he somehow managed to crank it and hurried down the shadowy stairs.
♦ Throwing aside the blanket, Ralph hopped onto unsteady feet. It hadn’t been a dream, of this he was sure. He’d heard that awful, terrified scream and it frightened him to the core. Grabbing his sweater, he threw it on and prayed softly as he rushed to the basement door. Could it be—there was a hidden room down there? Was there a ghost, like some claimed? Or was it something much more sinister? Another scream sent an icy shiver up Ralph’s spine and his hands shook even more as he fumbled with the stiff doorknob. Finally, the door swung open and he hastened anxiously down the shadowy stairs.
Ensure that reactions and responses yank readers into the plot and hold them tight. If characters are lifeless, or seem uncaring or unmotivated, chances are readers aren’t going to want to continue.
If there’s no reaction, the reader might assume the character doesn’t care or is oblivious to what’s occurred, and this may well be the case. Give careful thought as to how you write and edit a “no response” scene or scenario. If it suits what’s happening at that time, fine. Maybe Jeremy doesn’t get riled upon seeing someone kick the neighbor’s cat—and that non-response provides readers with insight into someone who’s non-caring. If a reaction or response doesn’t advance the action or plot, however, or provides the reader with a “huh?” or “duh?” moment, contemplate a rewrite.
A reaction can be physical (slap, bite, retreat, loss of consciousness). Make sure it makes sense for the action/scene and characters. Vary reactions. We don’t always respond the same way, with the same intensity; the same actions may even prompt different reactions, given when they occur and/or who’s involved. When editing, bear in mind how physical reactions add to conflict and tension.
A reaction can be verbal (reply, retort, slur, screech). When you use dialog as reaction, how will it advance the storyline? How will discussions and conversations rouse readers (such as make them sympathize with the protagonist or loathe the villain)? Like physical reactions/responses, allow dialogs to add friction (c-o-n-f-l-i-c-t). Something to think about: what your characters say is just as important as what they don’t.
Reactions could come in the way of thoughts and emotions, too. What characters are thinking or feeling reveals what’s going on in their minds and hearts. It provides insight into what they’re about, what they embrace, and what they believe holds true.
When editing, review how characters react to questions and comments, acts and actions. Do those reactions and responses:
⇒ seem logical ⇒ reveal character personality ⇒ develop character ⇒ vary in intensity ⇒ enhance the storyline/plot?
How your story progresses via actions and reactions is vital. Once you’ve engaged readers, the ultimate goal: buckle them in and take them for an exciting ride! 
The Writer's Grab-Bag 