>>1
The absolutely insane "DWIM" and "automagic" shit. No, while (<>) is not cool. No, missing parenthesis and having to guess what the fuck will it do in one or another condition is not cool. No, writing $x++ if ($x < 5); just because they botched the syntax and it won't support if ($x < 5) x++; is not cool. No, pseudo-Hungarian notation is not cool. No, backslash is a fucking ugly character and best avoided, so is -> as an operator, and don't even get me started on string comparison. No, there was no reason to change break and continue into last and next, and they sound ugly. No, $_ is not nice. No, I wanted function parameters, I don't like to have to write and maintain extra code to hack them out of a stupid list, and Python's solution is 10000x better. No, automatic global variables is not cool but the worst scope policy I've ever seen. And no, $< $| $_ $fuck don't make any sense to me. And I just mentioned the few easiest issues.
Not only you can write terrible code and Perl encourages it, but sometimes there's no other way but to write terrible code, such as functions. Everything related to functions sucks mightily.