This phrase evokes the freshness and vitality associated with spring, implying a person's cheerful disposition. She walked in full of the joys of spring, brightening the gloomy office atmosphere.
Pro Tip 2/3
Not Literal
It doesn't mean someone is actually carrying joys or spring; it's a metaphor for their mood. Despite the rainy weather, he was full of the joys of spring as he announced his engagement.
Pro Tip 3/3
Emotional State
Use it to describe someone's mood, not their physical energy levels. Even after a long flight, Mia was full of the joys of spring, excited about the adventure.