Work as sludge, and clearing the pipes

The concept of “sludge” has been getting a lot of run recently, in part because the book Nudge, which was pretty popular, just got a new revision and it talks often of “sludge.” Here would be a basic understanding:

One way to nudge people to do something is to make it easy to do. Sludge is like its sinister opposite: when institutions try to prevent people from doing something by making it hard…