Tigerstar's what ifs.
What if Thistleclaw was never his mentor? Would he not be evil? Thistleclaw taught him that rule breakers must be punished. Really punished. He wouldn't have hurt Scourge as a kit. He might have lived. He might have been nice. What if?
What if he killed Firepaw. He would have ruled, blood on his paws. Would he? He would have killed to get to the top. But then what? He wanted to rule, not to kill. Who would have lived? Whitestorm? Brindleface? What if?
What if he failed to kill Redtail? Would he have been banished? Would Redtail have killed him? Some cats would live. Would Ravenpaw have stayed? What if?
What if he caused the death of one of his kits? Would he have stopped? It could have made him realize what he was doing. He could have sofened. Would he care or would he be horrified? What if, what if, what if?