The Priest at my parish once told us that Mass doesn't begin when we get settled into the pew. It doesn't begin when the church bells chime or when the music minister strikes the first note of the entrance song. It starts when we wake in the morning. When we step foot out our door, get in the car & hop on the road to church, we have begun the Mass of both our individual spirits & the corporate spirit of the Body of Christ.
I imagine us like a bunch of blood cells entering the "venae cavae" from all different walks of life & geological points (The Venae Cavae are the veins that carry de-oxygenated blood back to the heart). How fitting that God should seemingly order the rhythm of our physical bodies to the rhythm of the spiritual Body... Or could it be the other way around?
When we go to Mass, we are returning to the Heart of our faith, namely, Jesus. And when the Mass has ended, we carry "freshly oxygenated" blood back to where we came from. I found it interesting to learn that while all arteries carry blood away from the heart, not all arteries contain the good stuff... What are we carrying away from our time with the corporate Body of Christ?