Bikes can take a lot of punishment. Sometimes though a component is so damaged it’s not clear how it’s even in one piece.
Take for instance this rim:
The sidewall was so deformed I don’t know how the join hadn’t split.
Then there’s this cone:
This was beginning to split. But more importantly, how was the wheel still turning?
Girl Parts 
Bearing races are great, keep tightening them up and they’ll spin just on the grease long after the balls have all ground down to nothing. Was that bike still rideable?
More or less. There was wobble in the rear wheel of a loose cone and a click suggesting a pit. Interestingly the bearings and the race were fine.
It was, although it often felt suddenly like it got exponentially more difficult to keep the bike moving. Kind of like the rear of the bike had gotten really heavy. It was particularly bad when carrying panniers.
I thought for a while it was just me not being fit, but was slowly getting convinced it wasn’t just me.