Discretion is the key! I'm no road rager so they don't get a lot of use.

Mostly people just look around for the train! No-one usually suspects it's the 30 year old golf that just made that noise.

You are right about people changing direction when they go off. So it's best to use them as horns are supposed to be used, to alert people of a dangerous situation rather than as an expression of anger.

Of course if there's no other traffic about and I happen to be passing through a tunnel or under a bridge I might lapse and have the occasional toot.

Pete