A whole bunch of stuff:
- Using a bad title for your node (see How do I compose an effective node title?).
- Not using any markup (see Perl Monks Approved HTML tags).
- Not previewing your node or, having previewed your node, not bothering to tidy it up.
- Not using correct capitalization and other grammar errors.
- Not putting code in code tags
Perl is environmentally friendly - it saves trees