For some people, reading fiction is like listening to a familiar pop song on the radio -- minimally engaging, pleasant, and soon forgotten. There are established writers who manage to deliver such reliable products again and again and make careers out of literary junk food.
I don't have any problem with this. I like the comfortable, the calm, and the easy at times, too. There are plenty of times when life brings all the challenges you need, and a few hours of escape are a blessing. The problem for a new writer is that this does not provide an opportunity to stand out.
With few exceptions, something easy and pleasant in a slush pile doesn't look much like a big hit to an agent or editor.
Strategically (and probably artistically), a work that is disturbing, topical, surprising, high concept, or from a fresh perspective is more likely to catch the attention of a gatekeeper. I'll focus here on what might be disturbing.
Certainly, subject matter can make a story stand out. Anything that touches on the seven deadly sins will, if done with honesty and directness, draw readers in. Pornography, which taps into lust, has a long, successful tradition as an area of literary endeavor. Lots of SF writers in the past got there start and paid bills thanks to this very open and insatiable market for manuscripts. (I don't know what the current market is like, but I note that Playboy's magazine can no longer get nude pictures to pay off. The world changes.)
One trick that works well is to move subject matter into unexpected places when the timing is right. Present bondage in a suitable way to interest suburban housewives and you can have a hit like Fifty Shades of Grey. Other examples have been adding sex to YAs, anti-heroes to Westerns, torture to high fantasy, etc. when the zeitgeist has called for it. Breaking Bad dared to bring genuine tragedy back to drama, and it will be interesting to see if this is repeated.
Speaking of anti-heroes, I was re-watching You've Got Mail recently. It occurred to me that, unlike its source material (The Little Shop Around the Corner), the main characters in this story are not very nice. In fact, Tom Hanks's character is appalling. If a less lovable actor had taken the role, the movie would have collapsed. But Meg Ryan's character, despite the unjust jeopardy she's in, is stepping out on her committed relationship with an emotional affair that is intimate and secretive. Her deep unfaithfulness might have been less visible when the world was not as savvy about the Internet, but today, we know over a third of women in committed relationships admit to having online affairs. These affairs are ending those relationships, so audiences might see her as less innocent now.
All protagonists should have flaws. There is room for protagonists with bigger flaws. If you bring Tom Hanks in, you might get away with a lovable mass murderer. (Dexter, anyone?) Handle it well, and your manuscript will be reviled by some editors and agents, but it will get picked out of the slush. I have a novel where a transfer student brings his humor and pranks to a school that has suffered a shooting. I have many notes of interest and praise from agents and editors, but some people have seen fit to write me long letters about how awful my character is and how awful I am. So make this choice with your eyes wide open.
I think the best way to disturb readers and make an impact is by creating villains they identify with. Naturally, you want to have three-dimensional antagonists who are motivated and have positive traits. Hannibal Lector (Silence of the Lambs) fulfills this and succeeds in eclipsing Clarisse in many readers' minds. To me, Gordon Gekko (Wall Street) is more disturbing. When I first watched the movie, I found myself almost being sold by him. He is complete, confident, and corrupt. He might have been the hero of the story.
While I found Gekko to be disturbing, others didn't. A lot of the people who caused the financial crisis in 2008 had become his disciples, studying him and justifying their actions based on his philosophy. Oliver Stone got attention and made a hit movie with a villain people could identify with, but he may have been too successful. There's a meme that says, "1984 was meant to be a warning, not an instruction manual." So, if you take this route to success, be aware of the unintended consequences.