[SgtBob]

You might want to learn more about your craft. You keep referring to “Center’s Airspace”. FL180 is a place I can’t venture...I fly 3,000, to12,000 IFR, depending on winds.

ARTCC is where nobody else is. Why do you think that Center only controls high altitudes?

[Yosemitest]

"FL180 is a place I can’t venture...I fly 3,000, to12,000 IFR, depending on winds."

That explains your lack of knowledge.
But you would normally talk to Center if you fly at or over 10,000 feet into most small airports, and while flying enroute at or over 10,000 feet.

[Yosemitest]

"ARTCC is where nobody else is."

WRONG!
Center Airspace is some of the busiest and most congested airspace in the air, all flying at high speed.
Remember, the earth is curved, so everything is eventually on collision course.
Small time pilots like yourself should go visit a Center and "Watch and Learn".
But your ego couldn't stand the "humbling".