There’s always one and usually more; check out any large group of cyclists where somebody needs to do something to their bike and, sooner or later, a cycle will be inverted before being placed on the ground.
Why? Er… the bike “stands up” on its own and it is easy to get the front wheel out to repair a puncture. Getting the rear wheel out of an upside down bicycle is a different matter while getting it back in without getting the chain in a tangle is an exercise in itself. At least it’s an excuse for doing something that not only risks scuffing the nose of the saddle and the brake hoods – before the introduction of concealed brake cables, of course, it was a certain way to kink the outer casing as it exited from the hoods – but instantly lowers the perpetrator’s status in the eyes of informed onlookers.
As for inverting the bike in order to give it a wash, as does one of the participants in the Sussex Surrey Scamble round of the Wiggle Super Series; surely it is better to get the tyre contact patches muddied by wash-off than those parts that are in contact with the hands and seat.