Undoubtedly one of the major contributing factors into MMA's popularity is the aspect of finishing an opponent. With smaller gloves and the ground game, a fight can literally end at any moment.
It's one of the features of the sport that has propelled it past boxing for a number of younger adults. Knowing that a fight could end at any instant and not having to watch a long, drawn-out decision is certainly appealing to a younger generation.
A number of fighters have used their ability to finish an opponent to become some of the most popular fighters in today's MMA. Whether it be via KO or submission, all of these fighters have talents to end their opponent's night at any point in a fight.