Two things rising together does not mean one is causing the other. Ice cream sales and drowning incidents both increase in summer, not because ice cream causes drowning, but because a third factor, warm weather, drives both independently. This kind of shared cause is one of the most common traps in reading any statistic.
Spotting it requires asking a simple question: is there a plausible reason the first thing would directly cause the second, or is there a more obvious factor that would explain both at once. Often, a little thought reveals a shared cause sitting quietly behind two figures that look, at a glance, like they must be connected.
This is not a reason to dismiss every correlation, since some genuinely do reflect cause and effect. It is a reason to treat a correlation as a starting question rather than a finished answer, and to keep looking for the mechanism before accepting the more dramatic explanation.