5. Randy Couture vs. Mark Coleman (UFC 109)
Many fans will tell you this fight between two legends of the sport should never have topped a card, but that's not true. It was a very suitable main event...in 1932. But in 2010, with a combined 91 years between them? Not so much. Randy "The Natural" Couture is famous for several things: winning titles in two different weight classes, running through women like training partners, appearing in The Expendables franchise and being a wildly popular fighter despite the fact that his strategy for the last few years of his career consisted only of hugging his opponent against the cage for 15-25 minutes. Mark Coleman is "The Hammer", the godfather of ground and pound and will forever be remembered for being disfigured so badly by Fedor Emelianenko that his daughters weeped uncontrollably at the sight of him. Both men are Hall of Famers, but with arthritis and dementia kicking in, they had no business facing each other. All kidding aside, the fight itself wasn't that bad, as Couture looked good in dominating the much more washed up fighter. But many fans had bought what the UFC hype machine was selling and expected the two grizzled old vets to march into battle and put on a show, and that just didn't happen. Mark Coleman never fought again after this and Couture was gone two fights later, leaving fans with some great memories, but this one isn't among them.