1. Keith Hackney vs. Joe Son UFC 4
When this happened it sparked a bit of a debate amongst MMA fans. Everyone had just watched a man win a sporting event after punching his opponent in the testicles. Some people felt that this technique should be banned. After all, certain moves were still banned at the time, including eye gouges. But while they were legal, Keith Hackney was the only guy to really utilize them to his advantage (at least in a high profile fight).
At first Joe Son became a bit of a sympathetic figure following this fight. But then in 2008, DNA testing revealed that Joe Son had participated in a gang rape in 1990. Now many people wish Hackney had hit him even harder in the nuts.
A month after receiving a life sentence for his crime, Joe Son is alleged to have killed his cellmate, who was a convicted sex offender.