Why do religions worship the cross?

this is one thing i do not understand. why do religions worship what Jesus DIED on.its like there worshiping what killed him and not what he died for..don't they think that makes God sad?imagine if your son was killed with an axe. what if people walked around with necklaces of your son with an axe in his head, or made statues of him being tortured by a man with an axe?wouldn't that make you sad?or make your stomach turn.we are made in the image of God so don't you think God would feel that same way as you do?sad?what do you think?