Or the fact that $FOO interprets as $(F)OO without the slightest warning. And of course if you're in a script line, you probably meant $$FOO..
Make certainly has some obscure variables, but of all the basic knowledge of Make you need to learn, $@ is near the top of the list (it's "target". an @ sign looks kind of like a bullseye. If you want to see it as visiting a dependency graph, it's the dependency you're currently "at").
