The creation of Ethereum Classic and Bitcoin Cash was primarily driven by disagreements within the cryptocurrency and blockchain communities regarding 'upgrades'.Ethereum Classic emerged from a split in the Ethereum community over how to handle the theft of funds from The DAO, a decentralized funding platform. A group of developers opposed rolling back transactions, leading them to create their own blockchain, Ethereum Classic (ETC).Bitcoin Cash was born out of a disagreement about Bitcoin's scalability. In 2017, Bitmain proposed a solution called UASF (User-Activated Soft Fork) as an 'emergency response' to the SegWit debate. This led to the creation of Bitcoin Cash (BCH), which has a larger block size and does not support SegWit.These events serve as examples of how community decisions can lead to the division of blockchain networks, creating new cryptocurrencies with their own unique features and characteristics.