Correlation between two variables doesn't mean that one directly causes another, because it can be a possibility that a third variable exists. So we can have variable A, B and C although not always a third will exist, but the possibility can be there. The correlation cannot demonstrate a cause and effect relationship. Sometimes we interpret things in a way that we assume two things are related, that's when we commit the correlation-causation fallacy. In conclusion, we need to have in mind that a correlation between two variables doesn't always demonstrate connection between them.
It brought to my attention an article named "TV in Excess Causes Depression", which describes that the more children spend seeing television, the possibilities of being a depressive adult increase. The believe that TV causes depression in a society that revolves around technology is scary, because through this media we typically get informed, entertained and even it helps to break the routine of daily life and relax. Don't you think we need to focus on what really causes depression? Everything in excess causes bad consequences. We know that seeing TV in excess can be bad because sometimes it results in avoiding exercise time and the hampering of social contact sometimes, but Excess of TV Causes Depression? Really? Shouldn't we be doing something different to control the time people spent seeing TV if it is that bad?