Some tools of language and expression are not considered "good" writing but can be excellent tools if used properly and not overused, for grabbing a reader's attention, developing a particular type of character, expressing exasperation, etc. Let's take a look at alliteration, for instance. This is the practice of repeating a consonant sound in close proximity to others...
...or beginning several words with the same vowel sound.
It's truly a fun thing to write alliteration, but if overdone it can be a real annoyance to a reader, and it can also appear comical in certain situations, possibly where you DON'T want it to do that.
Cacophony is the harsh grouping of words wherein the writer makes a phrase intentionally unpleasant to the ear when the spoken aloud. This practice is used to jar the dialogue or make a phrase particularly difficult to speak aloud.
Another tool that is considered generally "bad" in writing is an anachronism, which is placing a person, event, item, or verbal expression in the wrong historical period. Example: one would be hard-pressed to hear an Irishman in 1920 saying, "That's like totally awesome, dude!" Likewise, it seems pretty impossible that the ship in the photo below could actually be sailing on such a tiny trickle of water.
You can probably see how these tools could either hinder your story if used incorrectly or overused, or embellish your story if used properly.