I've seen this for decades, but it's much more common in Hawaii.  Half the drivers seem to let anyone and everyone go in front of them, either out of courtesy or "I don't want to be given stink eye", and the other half take advantage of that by always expecting the other car to yield regardless of who's in the right of way.

Watching some dash cam videos, it's obvious many drivers are either that arrogant or that oblivious that signaling somehow gives them the right of way, and the rest of the traffic is required to yield.

"Are you all right?"

"Why did you hit me?"

"I didn't expect you to change lanes less than a car length in front of me at 60 MPH."

"Well, I signaled, so you could have avoided the accident if you wanted.  This isn't my fault!"

 

Corollary:

Where does stopping to allow one car to turn left from opposing traffic come from?

Traffic flowing smoothly, some (usually a tourist) stops the whole highway to let someone make a left turn.

OK, if traffic is slow to stopped.  i will do it for locals, but never when things are flowing.

Almost rear ended a tourist or two that stopped for no good reason in the middle of the road doing this stunt.
Maybe they think they will be "local" if they do it, sort of like taking 5 minutes to back into a parking slot.

Corollary:

Where does stopping to allow one car to turn left from opposing traffic come from?

Traffic flowing smoothly, some (usually a tourist) stops the whole highway to let someone make a left turn.

OK, if traffic is slow to stopped.  i will do it for locals, but never when things are flowing.

Almost rear ended a tourist or two that stopped for no good reason in the middle of the road doing this stunt.
Maybe they think they will be "local" if they do it, sort of like taking 5 minutes to back into a parking slot.

That reminds me of this one driver that lives on the other side of Kuahelani from where I am.  A dozen or so times, I'll be at that light ready to turn left, and that car will be approaching while I wait.  They reach the intersection and STOP to let me turn left.   

I sit for a couple of seconds while my green is expiring since they don't bother to motion for me to go.  For all I know, they are going to get tired of waiting and T-bone me, in which case it'll be my fault. 

As you said , that behavior screws with the flow of traffic.  Plus, they are being unintentional dicks to the people behind them.

There's a reason all of us must follow rules of the road.

This mahalo and kokua crap only works (sometimes) when there is bumper to bumper traffic.  Otherwise somebody is gonna get killed in the name of "kokua" and "Aloha".

Follow the right of way rules.  Never mind trying to be the ambassador of Aloha.  I'd rather you give me stink eye and the middle finger while living to see another day instead of you ending up 6 ft. under the dirt.

Oh and by the way, driving has become the most terrifying and scariest thing I do every day.

Oh and by the way, driving has become the most terrifying and scariest thing I do every day.

You just stated the primary reason i gave up riding motorcycles in Hawaii -- the most biker-friendly-weather state I've ever lived in.  Although, i did kind of get tired of all those pineapple showers when riding.   

Kind of sad I had to risk my life unnecessarily to enjoy something I've done since I graduated high school.

You just stated the primary reason i gave up riding motorcycles in Hawaii -- the most biker-friendly-weather state I've ever lived in.  Although, i did kind of get tired of all those pineapple showers when riding.   

Kind of sad I had to risk my life unnecessarily to enjoy something I've done since I graduated high school.

I have to laugh.

Dec 1967, had an open R&R slot to Hawaii came up.  Buddy in the navy lived there, said come on over . lots of chicks, etc.
Not so many chicks, should have waited for Bangkok or Taipei.

Did so, buddy had no wheels, so rented a Triumph Bonneville.  Yeah, those mid-island rain showers.

Still, I felt fairly safe riding aroung the island.  No H3 of course.   H1 ended before Kahala IIRC.
Farrington (or whatever it was then) in Kapolei was like the slat flats, see how fast this thing can go.  ~115 mph, not impressed.

40 years or so later, move to Oahu, no way in hell would I ride a motorcycle there, not even a bicycle.

When did Right of Way get replaced with "I had my signal on!"?

When "I had my signal on"  was replaced by the shaka

When did Right of Way get replaced with "I had my signal on!"?

When "I had my signal on"  was replaced by the shaka

I thought the shaka was just a sign for "Yeah, I cut you off, ran the light/sign, and/or broke some other traffic law, but i'm special, and I'm more important than anyone else on the road."