Is this furball an old dog or a young dog?

Our poor pooch got abandoned today, in a manner of speaking. The mister had been cutting & carrying firewood all morning & when he finally came in tuckered out, we got him rehydrated & somewhat rested & then made a fast dash into town for groceries.
So getting back home, I pull the car into the garage & pop the trunk, we get out & start carrying groceries into the house & then Mister goes back for more woodcutting. He comes in a couple hours later & we fix supper, we eat supper & he takes off for the sofa & a well-earned nap. It isn't until two more hours that I finally wake up & think "where's Fritz?" I ask Mister about it & he begins to worry - then I start retracing our steps & have to ask "did either of us let him outta the car when we came home from town?" Nope - we just popped the trunk & away we went. Is this the most forgiving 80 lbs. of furball that ever lived? Yep - he was just still lying quietly in the back seat, waiting for someone to come open the car door. If we'd left the cat stranded for 4½ hours, he wouldn't speak to us for a week. But Fritz is now quietly sleeping at our feet in the living room . . . just like nothing ever happened. Geez . . .