Overengineering

Making software is like making a condo, in a few ways. You'll plan ahead what you want to create before starting so that waste is kept to a minimum. Contrary to a condo, where it's advisable to plan the whole project before you start, you do not have to plan out your software because it will most likely change during development, and a lot of the planning may just go to waste.

The problem with this "plan just enough" approach is that you don't know what to expect in the future, which may transform the little bit of paranoia we all have inside into something big. One may end up coding against total system failure or complex software requirement scenarios that may never happen. You don't need a multilayer architecture, with cache, database integration, signaling system, and so on, to create a hello world, nor do you need less than this to create a Facebook clone.

The message here is: do not make your product more robust or complex than you know it needs to be and do not waste...