There are plenty of aesthetic choices I see routinely posted on BF that I wouldn't have in my stable, but I'm not airing those.
Except for modern 4 arm cranksets - I'm calling those out.
BUT WHAT BUGS ME THE MOST is cyclists wearing pavement camouflage.
Matte black bike with black components and wearing a black jersey or jacket, (shorts get a pass, they have to be black) particularly while riding in low light conditions and/or lacking enough lighting on their bike.
When I see a cyclist kitted out like this, I'm almost tempted to run them off the road so I can stop and lecture them,
Yep, I'm getting old and cranky, too.