Smallville :

Clark discovers that Kara sent messages from Krypton in the past that indicate that Brainiac wants to kill baby Kal-El so Clark will not exist in the future. Clark is torn; he thinks the world might be better off if he had never arrived in Smallville.

Jor-El arranges for him to see what life would have been like if Clark hadnÂ’t existed: Lex is president of the United States, Kara is raised by the Luthors, Lana is happily married, Chloe and Lois are ace reporters and more.