I don't know if it's an evil side in me, or just a tendency to want to "do things right", but when I look at some of the spams that Spam Assassin catches, I can't help thinking I'd do a much better job as a spammer, and then go on to imagine how I'd go about it.
Take for instance a message that got rated 15.00 (I kill at 5.00). Summing up the errors in the headers (invalid date, date in the future, invalid to, MIME error, poorly faked Outlook headers...) you already shave off 8.6 points, down to 6.4. Only 1.5 points to go and you're below my threshold.
So what's left? I won't touch on the points it got for "high spam content", but the addition of all points awarded for several click-belows and click-heres with caps gives 1.6 points. That brings us down to 4.8, and voilà, the message makes it to my inbox (where it'll live a split second before I give it the del).
That wasn't even difficult, all I had to do was run it through SA. I'm sure that if I applied myself to it I could create a spam with the same content that would rate circa 3.00, a very safe value considering I get perfectly sollicited mail at around 4.5. By subscribing to the SA mailing list and becoming familiar with the code, I guess I could also exploit the negative points that SA sometimes gives a message. It's not like it'd be something that would require a highly trained programmer.
So if there's so much money in spam, why don't they hire competent people? As much as I'd like to believe that all smart people are also honest and wouldn't spam, I very much doubt it. Spammers really are stupid then...