And when car drivers flash their light at you, it might not be for anything bad, just maybe it is to warn you of something...like you don’t have you loving lights on and other road users can’t not see you that well.
Today on the north Deeside road, my darling wife thought she was about to see a crash

She was at the back of a line of half a dozen cars, a motorbike was coming towards them, then a van came out of a driveway in front of a motorbike.
The rider did have a hiviz top on, it was raining, but luckily there was no crash.
My wife thought the van driver did not see the bike.
A few reasons to have your headlight on...
...car drivers have many distractions...the sat nav, the radio, the DVD player, their phone, and often a pie or two to finish off, so anything to help make yourself noticeable might just stop a car driver dropping their pie because they crash into you.
...at this time of year it is getting dark early in the evening, still dark till later in the morning, and it is raining all the time...which makes the day time look very dark.
...vans, older vehicles, Landrovers of all ages...all have hopeless demisting systems, so the drivers cannot see a loving thing. Having your light on might increase the chance they will see you, therefore not put their vehicle in front of you and you won’t hit their vehicle and make a clean spot on it.