The following one is my favorite and I have seen this in practice in most of the places I have workd.
The Mythical Man Month, the idea that adding people to a development team makes it more efficient in a linear fashion.
One of my cow-orker said managers thing if you can not deliver a baby in 9 months alone they will make you do it by adding another 8 people in your team and giving you one month. The problem doesn’t end after delivering baby, none of the 8 people who helped in delivering the baby will care about the baby. It is not their baby at all. Another one which I noticed is at OSI Days talks is that OO a silver bullet, a golden hammer. Well, I work on web technologies and AFAIK, Google is bland but faster than any other known web app. More abstractions means performance hit. I want my page to load faster and if my code takes a minute to spit a text string my code is wrong how good OO patterns it may follow. Add to it the purists views of not adding markup to the script.