I remember this vividly when I was learning English for example back when I was like 6 or 7.
It was the letter N and S that I was writing backwards.
At a young age I had this uncanny ability to be self-aware in everything that I do and I would often try to figure out why I did things a certain way or why I thought a certain way and where those ideas came from.
Basically, once I learnt the proper way to write letters, I realised that the reason I was writing the letter N backwards was because it just felt more natural to start from the top and end up on the bottom.
If you try to write the letter N now, you realise that the only way to do it in one stroke to start on the left hand bottom and end up on the right hand top.
The only way you can start on the right hand top is if you do it in two strokes.
Therefore doing it in one stroke and starting on the left hand top just seemed more natural.
I do have to note though that by this age I had already learnt how to read from left to right, line by line, from the top of the page to the bottom of the page.
As for the letter S, this was a similar reasoning as well. In order to write it you have to start on the top right and work your way down to the bottom left.
Since we read from left to right that will be no logical reason to think that letters should be written right to left.
Another letter I had trouble with was the letter E. If you try to do it in the minimum amount of strokes possible, the only way to do it properly would be to start on the top right and work your way down to the bottom right.
I guess this is why most people write E in three strokes as opposed to one, since it just feels more natural to start on the left, work towards the right, and to move from the top to the bottom.
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