Living in two dimensions would surely give rise to a monotonous and dull world. It would be flat, without texture (literally) and uninteresting. Maybe then we would all just be normal shapes, depending on species and size. Possibly there would still be colours, although it would have to be dull, because there is no room for shadows or splashes of light in two dimensions.
Every shape would move differently and the bigger the shape, the more careful it would have to move since it could easily get stuck between obstacles, which are made more complex because of the flatness that causes the shapes not to be able to see over anything. But then again, will they see? Or merely sense? Seeing would be a waste, they will only see lines and possibly colours, no depth.
Movement would be confined to the compass directions, no going up or down. There would be no wind, no rainbows, no rain, no water, no fire.
There would really be nothing to do, or would there? Trading three dimensions for two seems not to be a fair trade at all. Does it even make sense to think this way?