To put it succintly, Microsoft Excel charts, either work or they don't. That makes it hard to train, particularly as the learning process with charts is non linear and the user interface is non linear as well, there are several entry points to display a menu and not all entry points are obvious. This is particularly maddening considering that Excel is such a comprehensively well thought out and planned program.
For example, if you have seen several series of data points on a chart and they are drawn on different vertical scales, you have to search Excel Help (well, now, it's actually Office Help) on "secondary vertical axis"
And although it's easy peasy to use your Excel cell cursor to highlight a chartable range and press F11, again, Excel maddeningly makes glaringly bad assumptions when your proposed X axis labels are numeric - Excel assumes they are another data series. Tip: Put a leading apostrophe on your proposed X axis labels to force Excel to treat them as X axis labels. Or go the painful way of Select Chart Area > Select Data