Notice that some wave back and others stare straight ahead, tightly gripping both grips, not daring to take a hand off.
There was a rider in our usual group that road like that even in a straight line.
Not only was it extremely frustrating but also dangerous.
This person would be in the middle of a 10 bike group and 5 riders in front of said person would make a left turn at an intersection, and said person would keep going straight ahead, meanwhile 3 of the 4 remaining bikes behind said person would turn left, and said person would keep going. It was then up to 'tail end Charlie' to go and chase said person, get it's attention and almost force it to turn around. On more than one occaison it was me who had to do the chasing (honestly it wasn't hard - I don't think they'd ever gone over 100km/h) and had to pull in front of it, progressively slow down and wave it to a stop.
It's response "I was wondering where everyone had gone".
The scary thing is that this person drove their Landcruiser the same way....
My ex brother-in-law (motorcycle cop) always said that he didn't trust a rider that didn't 'have a look at the scenery', it wasn't until I met the above person that I realised what he meant.....