I used to shovel snow from my car onto someone else's
What would be your reason to shovel snow onto someone's car?
My mom told me to do it. She said if I shovel the snow from my car; it would be useful and make sense.
While you are helping your own car by getting snow off of it, you are making it worse off for someone else. A better idea may be simply to put the snow into the grass.
It was just easier for me.
That isn't an excuse to then make things worse for someone else. Next time, place the snow on a pile on the grass.