
Incorrigible
Negative Tone
Incorrigible often has a negative tone, suggesting frustrating or problematic qualities that can't be fixed. 
Resistance to Change
Use 'incorrigible' to express that someone resists changes or improvements, despite efforts made by others. 
Not Always Serious
'Incorrigible' can be used in a light-hearted way to talk about less serious faults or quirks. 