Generally, when someone is accused of being a Rafida, it means that this person (rafidi) rejects Abu Bakr and Umar al Khattab. The Shias, since the earliest time, have rejected the caliphate of Abu Bakr and Umar. The Shia considers them (the first and the second caliphs) usurpers of the Prophet Caliphate and oppressors of Ahlul Bayt (namely Imam Ali (as) and Fatima (sa)).
Based on a hadith attributed to Imam Jaffar as-Sadiq (as), re-produced below, being called a rafidi should be a source of pride.
A man came to Ja'far al-Sadiq saying that someone had warned him against becoming a Rafidi and Ja'far replied "By God, this name which God has granted you is excellent, as long as you follow our teaching and do not attribute lies to us." Muhammad al-Baqir also mentioned an instance when he pointed at himself stating "I am one of the Rafida."
