so that other road users know your intention and know - for instance - whether or not they can emerge safely or are you subhuman filth who deserves summary roadside execution?
Good chap, psrb. I never doubted you for a minute.
My current (since 1995) bugbear is people taking full size bikes on rush hour trains, even worse is people with ****ing fold up bikes who don't ****ing fold the ****ing things up!!