amateurish and haughty way of doing business
Refers to a business approach that is both unskilled and arrogant, historically associated with ex-samurai who entered commerce during the Meiji period without proper experience or humility.
That shop's attitude is exactly the amateurish and haughty way of doing business.
From the business practices of ex-samurai in the Meiji period, who were often seen as lacking commercial skills while retaining a proud, condescending attitude.