Why did Caligula banish his sister Agrippina?

Caligula banished his sister Agrippina primarily due to political maneuvering and family rivalry. Agrippina was seen as a potential threat to his power, especially given her strong lineage and connections. Additionally, Caligula's increasingly erratic behavior and paranoia led him to view even close family members as possible rivals. Ultimately, his decision reflected the tumultuous and dangerous nature of Roman imperial politics during his reign.