Rest days. I get it. Our bodies need to recover from strenuous training, especially after returning from an absence. However, they aren't always welcomed. Don't get me wrong, sometimes I pray for that one day between my three and three training, but not always.
Some days you are just flowing. Training is going well and you don't want to stop the momentum. You know yourself and know that you could just keep going, but there's a plan and to deviate could potentially hurt your future efforts.
I've only really used strict rest days with lifting. Running or cycling I take a day off or reduce mileage, but it's not really structured.
I guess I view rest days as the responsible, adult thing to do now. So rest body. Take advantage. Cause when this day is done it's back to training and regaining the health we lost over the last year and a half.