Good data visualization is a balancing act. Communicating facts and statistics in a way that's both pleasing to the eye and conveys meaning intuitively requires skills that are not always easy to find.
It's not surprising when charts and graphs sometimes misfire, especially when the designer tries too hard to be clever and just winds up being confusing.
Just as shipwrecks are sometimes useful ways to spot where the rocks are, really bad data visualizations can help us avoid the mistakes of others.
WTF Visualizations is like a roadmap of how not to communicate data. I highly recommend you spend some time browsing their examples of really terrible data visualization.
First you will laugh. Then you will think. And then, I hope, you will resolve never to venture into those same waters.