There‘s a psychotherapist called Irvin Yalom who argues that all behaviour reflects psychology. Just as people who like to be on time are motivated by certain deep-seated beliefs, so those who make others wait are acting out an inner agenda, often based on an acute sense of power. There‘s famous footage in which Silvio Berlusconi kept Angela Merkel waiting while he made a call on his mobile. It speaks volumes.

Question 27. What is the ―speak volumes‖ in paragraph 2 closest in meaning to?