you would Buy because Better. Better is related to Mood. Mood is related to Emotion. 
Empty is a different concept from Remain. Remaining is a form of Remain. Remaining is a synonym of Balance. Balance is a synonym of Adjust. 
Buy --MotivatedByGoal--> Better <--RelatedTo--> Mood <--RelatedTo--> Emotion 
Empty <--DistinctFrom--> Remain <--FormOf-- Remaining <--Synonym--> Balance <--Synonym--> Adjust 