All Day Sucker by Stevie Wonder delves into themes of love, loyalty, and the feeling of being underappreciated in a relationship. Wonder uses vivid metaphors to express his feelings of being taken for granted despite his constant and unwavering affection for his partner. Key themes include devotion, disappointment, and the struggle for mutual respect in love. Particularly poignant moments in the song include the recurrent motif of being an 'all day sucker,' a candy metaphor symbolizing a person who gives selflessly but is undervalued.