Wait, Power Pivot! Don't Refresh Yet! I've Got More Changes!

My Tuesday morning was an exercise in patience waiting on Excel 2013. I was working on a complex workbook with a complex Power Pivot model with half a dozen complex PivotTables. After every minor change in Power Pivot, all the reports refresh. Hide a column. wait 2 minutes. change a calculation. wait 2 minutes. I finally got fed up with it, had a brain spark, and then my Tuesday afternoon was very productive.