As much as I love my children, I also love having them tucked into bed and off to sleep for the night.
For at 8 o'clock, it's my time. Granted there are times that my time still consists of chores, responsibilities, and duties around the house. But at least it's mine.
Eight o'clock is quiet. It's relaxing.
To me, reaching 8 PM means success - proof of another rewarding day.