Why do you put batteries in different ways?

Small batteries like AA's are 1.5 volts, so several are usually needed to power a gizmo at the right voltage. Its cheaper to wire the battery leads(connectors) if the batteries are reversed. Look at the way the little sprigs and clips are situated. Plus, it helps distribute the weight evenly if a lot are needed, like 4 or more. Also, the more batteries a device can have, the longer the electrical life it will have while in use.