I wonder if it would help to think back to the first time you littered? When I was 5 or 6, I remember eating a candy and not wanting the wrapper any more. It had to be someone else who saw what I did and pointed out that it isn’t good if we all did this, because then the playground would be all full of trash and we couldn’t play there. I was like, “Oh, I get it.” But if someone hadn’t explained it to me, I think the behavior could have innocently continued for quite some time. I grew up in a very rural place (northern Canada).