A good piece of writing for me is anything that doesn't portray its author as something he or she is not. If you are a racist bigot and your book defends racism, I might not read your book, but I would be okay with it existing. On the other hand, if you write a an intelligent sounding treatise on curbing racism, there will be undercurrents of shallowness in your writing that will annoy the heck out of the reader.
Such books are the advertising world equivalents of fairness cream commercials which ask women to develop confidence by telling them that their natural complexion is ugly.
And then there is funniness in false pretenses. There are writers who think they are writing an original thriller but eventually end up writing the most generic piece of work ever. There would be a hero, a sidekick, a crisis, a mystery and in the end it will all unfold not so shockingly. Some of course do not have any pretenses about their writing and that helps but, some writers use superlatives for their own hero. Every silly observation by their detective is a 'work of genius', every silly twist is 'so shocking!' For me, the superlatives are very close to self-praise and should be done away with.
In literary novels, there is a different kind of pretentiousness. The author tries to deviate from the topic as much as possible. There should be no plot and every character must have a background story. Sometimes, this ends up creating a very confusing picture. A grandpa character who could just have been a happy dude becomes an elderly figure who hates cats because he loved his son too much who abandoned him and his name rhymed with the name of a neighbourhood cat. It is also implied that the grandpa actually loves cats. Such entanglements create conflicted instead of complex characters. Also, in literary novels you have to describe every flower that is on the roadside. Attention to detail is good but, as soon as it seems unnecessary or forced, it turns nauseating. Unless your protagonist is a wine-sniffing, poet-cum-botanist, why would he be interested in the scientific names of the yellow flowers he saw once on his way to work? Keep it real.
Then there is the generalizing kind of writing. People feel a certain way and then they make a label out of it and paste on the world. People who are not comfortable in their skin try to make it a social issue. If no one talks to you, it is not because you're dark, fat or short. Yes, world is unfair but, not everything needs to be turned into a campaign. Sometimes instead of posting a one page status update on Facebook about how you feel women should not be judged on the basis of looks, you should just be thankful that the jerks who just see women as pieces of meat are not after you. Good people gravitate toward good people. Bad people attract needy pretentious people. It is that simple.