I have to admit that I do occasionally use them when its not foggy because the dipped headlights on our Z4 are pathetic: they are properly adjusted, bulbs are good, but maybe because they are so low to the ground they don't really illuminate the sides of the road very well. So on winding country roads in the dark I tend to use them to give better visibility as there's usually quite a bit of traffic so full beams aren't an option. They do get turned off again once I'm back on a a road with street lights. I know it annoys some people, but as it isn't actually affecting them and it keeps me a bit safer then I don't see what the problem is.
Park your car about a car length from a wall or your garage door.
If you put on your dipped lights (as you should) you see it all lit up low down (where the road is) but quite dark on the higher bit (where the eyes of the driver coming towards you are) this does not dazzle the oncoming driver.
Now put on your fog lights and you will see that you are now lighting up the whole of the wall with much more in the higher bit where the oncoming driver is. It is not as much as full beam but nontheless it is still throwing much more light into the oncoming drivers eyes.
So please now ask yourself if you would like a driver in 2 tons of car coming towards you with good visibllity and able to see where they are going or blinded by some idiot with too many lights on so that they cannot see anything (while they can clearly see you and all your lights they are blinded to a) a cylist or pedestrian, b) hitting the kerb or something and beng thrown accross in your path.
So please only use fog lights in the fog only before you kill someone or yourself.
While you may better your own visibiltiy should not be at the cost of others visibility?
It is illeagal and rightly should be.
Clearly you are deluding yourself that it is not affecting others when clearly it is affecting them or they would not be annoyed with you and desperately trying to tell you that you are blinding them.
I really am amazed you passed your test. But perahps that was before you bought the BMW and adopted the standard attitued of such drivers.