thank you (for your hard work); I appreciate your efforts

anxiety; worry; concern; cares

difficult situation; adverse circumstances; predicament; trouble; dilemma; distress

bitter cup; bitter experience; bitter defeat; ordeal

complaint; troubles; objection; grievance

not one's cup of tea; not one's favorite

pain; anguish; distress; suffering; hardship

(mental) agony; anguish; suffering; distress

pain; agony; suffering; distress; torment

bitter

hard fight; close game; struggle; tight contest

racking one's brains; worrying oneself; being anxious