...it took me 30 minutes to figure out that it was giving me broken code examples, wrapping variables incorrectly in parens, like:
(format t "You rolled a ~d" (dice-result))
...I still don't really know if I'm learning properly so it's pretty funny in that way. But overall it helped me make a lot of headway so far, even though it made me curious how much time it's caused other people to waste.