Be nice. ;)

The OP said I have little Perl experience which also means he has very few Perl habits, bad or otherwise. The strong implication is that this is in the context of inherited (and likely fairly old) code. I'd imagine that the OP was feeling a bit battered by the code before coming here for help, so a gentle "here are some things to watch out for" will go down much better than the implied "here are some dumb ass things you did".

++ for helping the OP learn by highlighting issues and pointing to documentation, but be a little aware of how tone affects message: it's the sugar as helps the medicine go down.