Fundamentally, writing is communication. Yes, it includes sound values, wordplay, images, allusions, and a fair share of nonsense and fun. (Anyone who has ever listened to comedian Sid Caesar's gibberish knows how far you can go with no attention to syntax and still succeed.) But confusing readers is one of the fastest ways to drive them away.
Making everything you write clear and unambiguous isn't easy. Robert Heinlein claimed that the best writing course he ever took was one where, in the US Naval Academy, his teacher presented military situations to the students and asked them to write orders on the blackboard. If anyone else in the class could misinterpret an order, the day's work was a failure. A job I had early in my career was even harsher. I had to write procedures for purifying enzymes and nucleic acids. Errors could cost the company a lot of money, but, worse, they could threaten the health of the lab workers.
In that case, my readers often did not have English as their first languages, and it taught me lesson number one: Know your audience. What words do they know? Can simpler terms be used? What is their education? Are they familiar with your references? Expressions? I used the phrase "In for a penny, in for a pound" in a Young Adult novel I was writing, and my daughter called me on it. Your assumptions about what people know about history, songs, public figures, and scientific facts may be wrong. Which brings up another lesson...
Get another pair of eyes. If possible, find beta readers (non-writers who will read complete manuscripts), and explicitly ask them to mark places that are confusing, unclear, or need to be read more than once. Ideally, you want someone who is likely to enjoy what you are writing. Genres have different demands. When I write science fiction, I can count on readers to be more comfortable with learning about new terms and concepts as the story unfolds. (James Tiptree actually recommended writers "drop readers in dark holes, and then don't tell them.") On the other hand, romance readers who read SF romances often don't have the same tolerance for uncertainty. They want the SF concepts clearly explained as they are introduced. (These same people would attack you if you explained all the secrets keeping lovers apart right away.)
Story logic can be another stumbling block. Leaving out clues and essential concepts (or introducing them in the wrong order or at the wrong times) can leave readers scrambling to put the puzzle together. And the emphasis or context is important, too. Mysteries play with this notion by purposely introducing red herrings and by creating distractions to make important clues less obvious, but this is dangerous business. Do it outside a mystery, and your wit may not be appreciated. Do it wrong in a mystery and you'll frustrate even these readers, who will feel cheated. Revelations in all stories must be handled with care.
The most common failures of clarity I see are places where it isn't obvious who or what a pronoun refers to or where there's confusion in the dialogue as to who is speaking. Fix these.
It is reasonable to push your readers' vocabulary -- slightly. Coming up with a few new words in a book can be a delight, provided they are the best words for what is being conveyed. Dialogue that is "on-the-nose" sacrifices subtext and opportunities to express character. And all art seeks subtlety and ambiguity that can extend the range of interpretations. But there is no room for showing off your vocabulary, wit, and intelligence to the point where you are frustrating and humiliating your readers. Resist the urge.