Why does correlation not equal causation psychology?

I believe Correlation is not causation" means that just because two things correlate does not necessarily mean that one causes the other. As a seasonal example, just because people in the UK tend to spend more in the shops when it's cold and less when it's hot doesn't mean cold weather causes frenzied high-street spending.

You don’t list any options but the one that frets overspending and the consequences of that.