If you use it here in California other drivers take it as an invitation to block your intended action.
Ha! It is a turn indicator, not a turn-may-I-please-maybe-change-lanes-or.
I have a short commute, and watch my mirrors to keep tabs on traffic. I know pretty well which lanes back up where (turn in at Walmart, bus stop, etc), and generally change lanes in advance to avoid traffic backing up.
However, when I have several car lengths of room, turn on my turn indicator, and the jerk in the other lane decides to speed up to try and block me, I take that as a sure sign they've seen my car and see my turn indicator light. I usually let them get about half a car length off my bumper, then I change lanes.
So far, zero of them have hit me. It's the damnedest thing.
I'm only worried about getting in wrecks with people that don't see me.