In combat Sports there will always be controversial decisions. Some more controversial than others here are some of the worst decisions in mma's history IMO.
Their weren't bad decisions in the first 8 UFCs mainly because they did not have judges however, UFC 9 would serve as the first time a UFC SuperFight had judges, I will not include this fight as one of the worst decisions ever mainly because neither Shamrock or Severn deserved to win this fight, however, the fact that a local hometown basketball player from Severn's hometown was the deciding judges decision is laughable at best.
In my opinion the first really bad decision in the UFC's history was the Pat Miletich vs Mikey Burnett bout that would determine the first Lightweight (now Welterweight) Champion in the UFC. How Burnett lost this fight is a mystery to me, he took Miletich down multiple times, knocked Miletich down with strikes twice and seemed to control the match. Burnett refused to fight in the UFC unless he got a rematch (which he never did).
Then at UFC 20 in a pretty similiar match, Bas Rutten somehow defeated Kevin Randleman for the Heavyweight Title, the judges must have thought Bas effectively controlled his bleeding eyes or something cause in the fight I wastched, Kevin Randleman controlled the bout and position, landing multiple takedowns and bloodying El Guapo.
Randy Couture defeats Pedro Rizzo at UFC 31 - seriously, how do you not give Rizzo 3 rounds, I gave him 4. Led to an immediate rematch which led to a pissed off Randy and another UFC champion bolting from the organization.
Alan Goes vs Dan Henderson - seriosuly watch this match and tell me how Hollywood wins this one.
Guy Mezger vs Ricardo Arona and Kazushi Sakuraba - Guy did more during the fight against Arona and vs Sakuraba he nullified everything a prime Saku had to offer, stuffing him over and over, landing strikes standing and controlling position on Saku. Most enfuriating draw I have ever witnessed (could have gotten Guy vs Royce)
Bisping vs Hammill - I dont think any explanation is needed.
Leonard Garcia vs Damn Near Everyone - I guess you just have to keep coming forward and winging wild arm punches to win fights these days.
what are your adds???