Definition:
Waterfallacy is a mistaken belief or idea about agile or Scrum created from working too long on waterfall projects.
Many of the specific arguments heard against Scrum are predictable and common across many organisations. Some examples of waterfallacies heard are scrum requires everyone to be a generalist, scrum team don’t plan, our team is spread around the world, self-organization clashes with some cultures, so we can’t be agile, scrum requires face to face communication, scrum ignores architecture, scrum is ok for simple websites but our system is too complicated.
Further Reading:
Book: SUCCEEDING WITH AGILE Software Development Using Scrum by Mike Cohn