Indeed, like we physically did with the piece of paper, we have mentally chosen to think of our image in the mirror as like ourself but turned horizontally (aro

Indeed, like we physically did with the piece of paper, we have mentally chosen to think of our image in the mirror as like ourself but turned horizontally (around the verticle axis) to face us - ending up flipped left-to-right. If we instead think of our image as like ourselves but turned vertically (around the horizontal axis) - like you lept headfirst into the mirror and landed upright on your head - then you'll find that your left and right sides are the correct way round but the image is vertically flipped. It's very hard to think this way because (a) we're mostly symmetric horizontally, certainly a lot more than vertically, and (b) we very often interact with other people that have turned horizontally (around the verticle axis) to face us but very rarely interact with other people that have turned vertically to face us. Another aspect that makes this hard mentally is that if you have any identifying non-symmetrical features, like birthmarks, then they appear horizontally flipped in the mirror compared to photographs. Again, it's the photograph that's turned incorrectly. This one is particularly hard to sell, because surely a photo with a ground at the top can't be the right way round? The answer is, for the purpose of matching your left and right, the "correct" way round is for the photo to face away from you. Makes logical sense, but very unintuitive.