We see things come into being and leaving; birth and death; the extinction of the dinosaur, the various endanger species, for example.
Our conceptualization of the world around us changing from that of a flat earth to a sphere:
For centuries, mankind knew all there was to know about the shape of the Earth. It was a flat planet, shaped roughly like a circle, with lots of pointy things hanging down from the underside. On the comparatively smooth topside, Europe sat in the middle of the circle, with the other continents scattered about the fringes, and parts of Africa hanging over the edge. The oceans lapped against the sides of the Earth, and in places ran over, creating currents that would pull over the edge ships that ventured too far out to sea. The space beyond the edge of the world was a dark realm inhabited by all sorts of unholy beasts. Fire and brimstone billowed up from the very depths of hell itself and curled 'round the cliffs whose infinite length jutted straight down to the darkest depths . . .
Our culture evolves through various, often unnoticed, influences. I remember my grandmother complaining that baking flour was different in Canada; she couldn't make her cakes. The impact on the continuity of culture as women move out of the home into the work place. The impact of the emergence of fast food restaurants on the French Bistro. The iPod is killing "Rock Snobbery."
Each parting leaves a gap; may be perceived by our minds, yet not fully understood or appreciated and only rarely receiving any consideration. Their replacements take shape and fill the void and then they become the new normal and our memories of the old way pass into long term memory and then end with us.
Good or bad? Neither, it just is.