I recently had a game approved and the entire review process took less than 4 days. After it was approved, it took about 6 hours for it to show up in the store

I recently had a game approved and the entire review process took less than 4 days. After it was approved, it took about 6 hours for it to show up in the store. This was my first app so I figured I'd be waiting at least a few weeks. I was happy (and very surprised) to see it accepted so quickly. I have no real idea of what causes the varying review times.