Perl lets you be sloppy which is ok on a 1 to 5 line script. Some 'programmers' (and I use the term loosely) don't realize that there's a difference between these 1-5 liners and a 3000 line app. I just finished helping someone on the DBI list who thought that 'use strict' was 'too much trouble' and yet it would have helped find the problem right away (system table names with '$' in the name getting interpolated in double quotes).

I've seen one programmer avoiding arrays because he thought they were broken (He had bad input, and didn't know how to debug CGI code from the command line - he'd only run it from the browser). And he didn't use hashes because he didn't know what they were. Update: and he didn't use placeholders in DBI...now there was a weird issue where directly pasting the value in the SQL worked ok, but using placeholders it did not because of a newline in the data. Again, it was another place where debugging in the browser was insufficient (Gee, I printed the variable, and it looks ok...).

Bad programming is possible in any language (see How to Write Unmaintainable Code), but perl lets you be really bad if you want to be or don't know any better.