Simple categories matching troublesome:

• work,
• problem,
• behaviour,
• symptom,
• material,
• substance,
• component,

Members with property troublesome:

• resin,
• stress,
• leg_pain,
• substance_misuse,
• feather,
• wax,
• pain,
• heartburn,
• encaustic,
• bullying,
• abdominal_cramp,
• headache,
• phosphorus,
• aluminum,
• municipal_waste,
• dust,
• persistent_pain,
• dizziness,
• withdrawal,
• constipation,
• bone_pain,
• soreness,
• compost,
• delinquency,
• urgent_diarrhoea,
• dyspnoea,
• nausea,
• enamel,
• waste,
• sand,
• phosphate,
• pvc,
• colic,
• palpitation,
• swelling,
• sulfate,
• sneezing,
• diarrhoea,
• spraying,
• bismuth,
• haemoptysis,
• aggressive_chemical,
• aggression,
• gravel,
• transient_dizziness,
• sickness,
• construction_waste,
• joint_pain,
• acidic_clay,
• chrome,
• shrimp,
• semaphore_deadlock,
• apathy,
• dysmenorrhea,
• drinking,
• burning,
• depression,
• sulfur,