First anti-pattern in Ladd's talk. When an entity method takes a command message as a parameter, decodes its attributes, and returns an event, the entity's cohesion drops sharply: interpreting command attributes is a messaging concern and belongs in a handler, and returning events couples the entity to event sourcing specifically. Clean entities look like a domain specification and could be swapped to an ORM with no change — entities are your biggest, strongest asset; don't give that up easily.