Damned by nature to try to calm you down .... but seriously... I can see why you might see this. The fact that the space bar is 3 keys wide seems to give it the appearance that's it's not as tall as the other keys. Each key has a convex shape to it. Even if the space bar has that same shape.... it will have a much longer surface where it's flat.... giving it the impression that it's lower that the other keys.... which seem to be rising slightly higher.