The Sunni and Shia have had a huge political impact on the Muslim world. At the time of Muhammad's death there was a big question of who would take over and be the new caliph. As we know the Sunni wanted the caliph to be someone capable and responsible enough for the job, such as Abu Bakr. The Shia wanted Muhammad's cousin/son-in-law, Ali to take over and be caliph. These two groups stirred up a lot of controversy because people back in those times would have to choose which side they were on.
Along with the five pillars of Islam, there was also another detail that is not considered a pillar, but is still recognized. It's that all Muslims respect the Prophet's family, ahl al-bayt meaning "people of the house," Since the Sunni wanted the best candidate to become caliph that was the difference between the Sunni and the Shia.
