CockroachDB emphasizes the importance of strong transaction isolation by default, specifically the SERIALIZABLE level, to ensure data consistency and prevent subtle bugs that can arise from weaker isolation levels like READ COMMITTED or REPEATABLE READ. While many databases prioritize performance by defaulting to these weaker isolation levels, allowing for potential anomalies or "lies" in data processing, CockroachDB opts for higher safety standards. The SQL standard endorses SERIALIZABLE as the default due to its robustness against transactional anomalies, but many systems, such as Oracle and older versions of PostgreSQL, either implement weaker versions like snapshot isolation or do not support SERIALIZABLE effectively. Recent research highlights the real-world impact of weak isolation, uncovering transactional bugs in eCommerce applications that could have been avoided with stronger isolation. Despite workarounds like SELECT FOR UPDATE, which aim to secure transactions under weaker isolation, they often fail or introduce performance drawbacks. CockroachDB's approach prioritizes data accuracy and reliability over performance, aligning with findings that highlight the risks of weaker isolation and the challenge of implementing effective workarounds.