I don't think it's a motorcycle rider thing and in if fact is an island thing.

As Ruralcarrier states there are certain states within the USA that allow for personal choice of wearing a helmet. Two the states that I have lived in don't require helmets, one being New Hampshire and the other Florida. When I lived in NH you would watch the motorcycle riders coming from or going into Massachusetts stop at the state line to remove or put on their helmet because it is required in Mass but not in NH. Now in Florida a rider over the age of 21 who has medical insurance in excess of $10,000 (Basically a health insurance policy) does not need to wear a helmet Having been an avid motorcycle rider until recently due to back surgery, I would never ride without a helmet.

As for the DRIVING PRACTICES, that's where the rub is. In every state it is illegal to pass, in any type of vehicle, on the left unless there is a broken line, white for multiple lanes in same direction and yellow for opposing. It is also illegal to pass on the left on the crest of a hill, a vehicle turning left. I have seen these morons pass on the left into oncoming traffic and they EXPECT the driver in the oncoming lane to yield to them.

As a retired law enforcement officer I can tell you that type of behavior was not tolerated and it also causes many unneeded deaths.

So, yes in my opinion, IT'S AN ISLAND THING.