Yak Shaving - I like that you have a word for the concept of a simple task that can break down into lots of complex things.<p>Where I work we do low and high estimates (in hours, no scrum) but there is no way to express "this may take 1 hour but if the system is horribly enough designed in that area it may take 1 month" - in which case perhaps we should decide if it is worth it.