Any place you go, there are different driving styles. In Los Angeles, I was very careful to always turn on my turn signal and let it cycle at least twice before turning or merging into the other lane. The drivers in Los Angeles are aggressive, but everyone knows everyone is aggressive and expects it. Using turn signals was required not because you were smart, but because everyone else was dumb with distractions and aggression.
In the San Francisco Bay Area, there's still the aggressive driving, but no where near the level of Los Angeles. In SF, you wouldn't turn left between two oncoming cars unless there was three car lengths between the cars. For comparison, in Los Angeles, you need only one and a half car lengths, even when cars are going 50mph.
Driving around here, I'm far more relaxed, causing my signal turning routine to soften. I haven't been using my turn signals at all if there isn't anyone behind me when I move into lanes. I hadn't really noticed until it was mentioned to me, in the most approachable criticism I've received about my driving in a long time.
"I'm surprised how much your lack of turn signals bothers me."
How's that for approachable criticism?
It addresses the issue: my lack of turn signals.
It doesn't pass judgement. There's no, "You're an awful person for not using turn signals," or "You're going to get us killed from not using turn signals!"
It brings up the topic without accusing me of doing anything wrong.
It gives me the opportunity to see my behavior is affecting others.
The rest of the drive home, I used my turn signals, even when there was no car behind me to see my intended movement. I may have over-used them, if that's possible. I did notice, however that one oncoming car that arrived at a four way intersection at the same time as I did, stopped fully and waited for me to turn. I suspect the left turn signal may have indicated I was going to turn. Normally, I would have just waited for the other car to go.
So, yay, turn signals!