It's called "attention whoring." Jack Cade just can't bear the existence of any topic that isn't about him.
Brittanicus: Caesar, this is improper!
Theodosius (outraged): How?
Caesar: Forgive him, Theodosius, for he is a barbarian, and thinks that the customs of his tribe and island are the laws of nature.
-- G.B. Shaw, Caesar and Cleopatra