I have just wasted about two hours of my life trying to figure out how to make R draw a line graph (all I want to do is plot the conditional mean of a variable on the Y axis for certain categories of another variable) to stick in my undergraduate methods lecture for tomorrow—a graph I could have constructed trivially in Stata, Excel, or SPSS in about 15 seconds. This is patently ridiculous.

I am not an idiot; this should not be so hard to figure out. I like R, but it is actively user-hostile (even with Rcmdr and other packages loaded), and until it ceases to be such I will not foist it on my students.