The video above of Google's Matt Cutts is rare in that he often doesn't show this much emotion and feeling in his videos.
He ranted about how so many people fall for "snake oil scam SEO" and then fall for it again and again.
Here are some quotes from the video, but this is a fun watch:
You're a webmaster and you don't realize that these people have 10 sock puppets?
You go with the guy who has trashed 10 websites, but he promises this time is different?
That guy doesn't know how Google caught his domain [that was penalized], he has no idea the different techniques or tools we are using.
At the end, Matt makes the plug to just go white hat now instead of playing the game.
Forum discussion at Google+ and Google Webmaster Help.