I tend to agree...

However, on the "competitive" end of things, I think So Cal drivers tend to be a bit more wrapped up then other areas of the country. If I am driving along and signal well ahead of my desired lane change or exit, often times that "drop out of the game" mentality will leave me stuck in the same lane as motorist after motorist flies by my vehicle, which is doing speed limit... no matter how long they have had to give way to my request (which is what a turn signal really is) I find that eventually I have to make a very definitive move to make a gap. I have also had motorists respond to my definitive move with one of their own. (The really annoying issue is when you are trying to get on the freeway... and someone is trying to get off and they don't let you move over while they hold their position... they pass you to then turn in)

Cycling is not nearly so bad... as you were indicating earlier that a head turn sometimes can be just enough... I too have found that to be true... as long as there is not a huge speed difference. But when I am on a 45-50MPH arterial and need to make a left turn... sometimes it takes more then a head turn and arm signal... it takes moving over a bit to show that you really do intend to make that move. It is a gutsy thing to do, and you really need to verify that the traffic will slow down for you... (I find that staring down the driver while you make the move helps).

It really should not be all that difficult... as "atbman" said, it should be a co-operative thing... but it just ain't so.