So, imagine you get a CR passage which starts off with telling you how people who move to coastal cities tend to find employment faster than before. The passage concludes by saying places (such as NY and LA) must therefore have better employment opportunities.
How do you perceive that sort of argument? An actual OG passage may be a little more complex and may not make it so clear, but if you can note that all this is basically saying is that:
situation A was followed by situation B
Therefore A caused B.
What GMAT alarm bell should be ringing? Well, one would be that A does not necessarily have to cause B. Perhaps such people are more motivated to find employment in a new city.
The point is not whether this is actually true or not. It's recognizing that on the GMAT this is a familiar type of answer choice you'll see thrown your way. The next time you see a CAUSATION passage, perhaps you'll be more hyper sensitive to it!
All the best.