If it sucks to be someone right now, that is probably Alexander Gustafsson. Gustafsson was involved in one of the best UFC Light Heavyweight Championship fights of all time against Jon Jones, losing a razor-close decision to the dominant champion. Finally Alexander Gustafsson was going to get his rematch at UFC 178, but a knee injury prevented that, leading to Daniel Cormier getting called up for the shot.
Here is a crestfallen Alexander Gustafsson giving everyone a brief update on his injury. Apparently the injury will only sideline him for a few weeks, which makes the loss of his title shot all the more disappointing for everyone.