... and sign up and monitor every FBL you can get your hands on, have outgoing spam filtering gateways, procedures to rotate subnets in case Microsoft/Outlook/Hotmail receive a single complaint about any message relayed by your MTA and take their sweet time "conditionally mitigating" you. Pray daily that none of your users get their email creds stolen on a coffee shop wi-fi.

It's a very lame part-time job.