Making left turn -- how far left is left?

Dear rec.bicycles.misc:
Here's the setup. Making left turn at signaled intersection. Slight
downhill to intersection, then flat. It's a T- intersection, the
options are left, right or Rubio's Fish Taco's straight ahead (#1 for
San Diego denizens). Postal collection boxes on corner at right. I'm
roaring down for a left turn, but the light turns yellow while I'm
about 25 or 20 feet away from the intersection, so I brake (both hands,
didn't signal the stop there, my bad on that). Extra special complexity
-- one of the new USPS 2 1/2 ton dual role collection/delivery vans is
smack dab on the right while the "letter carrier" is sorting out
parcels, flats and envelopes into the appropriate tubs.
White SUV (big one) with mom and boy, roars in for a right turn all
of five inches from me, and she's MAD about having to stop, or about
nearly rear-ending me, or both. Mom immediately berates me for not
going through the light -- to which my reply was "At THIS
intersection?" And then I decide to clam up, more or less, because the
road isn't usenet, and with her kid in the vehicle with her, Mom can
NOT afford to be wrong. Ever. Any protestation will lead to escalation.
Besides, who am I to say I'm perfect? Also, it's not the greatest
neighborhood economically, so the usual drivers of shiny new SUVs with
kids are heading to/from the medical offices nearby.
Mom the driver then points out that cyclists turning left go "all
the way to the left." I look down -- center line of bicycle is about 18
inches from the double yellow.
I thought the "Have a nice rest of your life" was a bit gratuitious
on her part, but with an attitude like that, I'm glad I didn't get into
it with her (see above about how she can't afford to be wrong, because
she's in the presence of her child).
So, now that I've done venting about what was said/not said in a
somewhat safer forum than wedged between a traffic stop and an SUV,
I've got to ask, how far left is "left?" Especially at an intersection
where the left turns from the perpendicular lane are often taken
sharply by folks trying to get into the 7-11 parking lot in one smooth
manuveur?

Robert Leone