All those things are true.

$_ and @_ are confusing largely because there's no single piece of documentation which lists all the functions that assume $_, which functions will implictly set it, and so forth.

I'd add: perl is inconsistant. $_ acts like an alias inside a foreach, but doesn't have the same side effects outside the loop. @_ means @ARGV, or the parameter list, depending on whether you're in the main program body or not.

Perl lets you do things in inconsistant ways: this is part of the TIMTOWTDI design. Once you let there be multiple ways to do it (inconsistant design, that accomodates multiple ways to do the same thing), you don't worry about a few more inconsistancies thrown in here and there, even if they're confusing to a novice.

Try explaining the word, let alone the perl implementation of the term "autovivification", and watch the eyes glaze over really fast...