Shakti is the active manifest form , creation and creative power.
The two are not different yet different in expression. .
The two forces are present in our own nature.
The tendency to be Silent observer is the Shiva; the tendency to create, celebrate is the Shakti part.
If we have only one side developed then it may feel like a burden after some time. If we try to hold onto only one then we are in conflict with our own nature.
After the peace of chanting/Kirtan/meditation/any other form, we naturally want to share the joy with others. After sharing, we want to go back to the silence.
This is the familiar dance of Shiva and Shakti in our own life expression.