The Pleasure of Disagreement

We're starting a new phase.

"We're going to the park this morning," a statement that would usually be greeted with glee, is met with, "I don't want to go to the park."

Oh, really?

"Okay," I say, "We'll just stay home."

"I want to go to the park," he responds.

In the past 72 hours, we've had this same conversation about 20 times, just insert a new subject into the blank.