積重難返

ingrained habits are hard to overcome (idiom); bad old practices die hard

to repeat / repetition / again / re- / classifier: layer

heavy / serious / to attach importance to

to return (to)

to amass / to accumulate / to store / measured quantity (such as area of volume) / product (the result of multiplication) / to integrate (math.) / to solve (or integrate) an ordinary differential equation (math.) / old / long-standing

difficult (to...) / problem / difficulty / difficult / not good

disaster / distress / to scold