I think my right left confusion might be because I am not strongly right-handed. Don't know if I would have been left handed if I hadn't been taught otherwise or if I'm just ambiclumsy. But if I'm painting a wall (say) I use either hand and avoid moving the ladder so often.
A lot of children write numbers back to front 15 instead of 51 or the 5 reversed.

If you hold up your left hand - palm away from you the thumb & fingers make a letter L.