What other theme is addressed in the passage?

Liam's first job at the fast-food chain was not glamorous. He worked early-morning shifts, loading biscuits into ovens and dipping countless batches of hash-browned potatoes into vats of grease. Every day he encountered harried, impolite customers and complaining coworkers; nevertheless, he maintained a positive outlook. Liam methodically completed his duties: wrapping sandwiches, filling orders, and cleaning his work space. Liam's manager appreciated his diligence, and by his third month of employment, he was no longer assigned to the pre-dawn shift. Within a year, Liam was an assistant manager earning double his initial pay.
Theme One: Every job is worth doing well.