When is showing off considered major idolatry and when is it minor idolatry, and is the prayer of one who intends to seek people's praise considered major or minor idolatry?

Ostensibly, hypocrisy can be major polytheism (shirk akbar) if it pertains to the very foundation of faith, like the hypocrisy of the hypocrites, or if all worship is performed for the sake of people without intending the countenance of Allah. However, hypocrisy emanating from a Muslim in some of his deeds is minor polytheism (shirk asghar) that does not expel one from the fold of Islam.