But in all seriousness, I've had to teach Perl from scratch to multiple people (who were already programmers, just not Perl programmers). I taught them about how to use closures for creating dispatch tables and never had a problem. They picked it up easily, used the technique in Perl, and treated it like they did regular expressions: just another convenient construct that was available in Perl but not C.

Note that I did not show them all possible uses of closures, just the one specific case which came up a lot in that codebase.