It's true that Excel is responsible for large numbers of horrible charts. I just came across a typical example recently:
This figure comes from Edward Wolff's 2012 paper, "The Asset Price Meltdown and the Wealth of the Middle Class." It's got all the hallmarks of Excel defaults. It's not a pleasing object to look at.
However, it's also true that Excel can be used to make nice charts. Here is a remake:
This chart is made almost entirely in Excel - the only edit I made outside Excel is to decompose the legend box.
It takes five minutes to make the first chart; it takes probably 30 minutes to make the second chart. That is the difference between good and bad graphics. Excel users: let that be your inspiration!