As a Software Engineer, which library or framework was a gamechanger for you?

Personally for me? Shifting from pandas to polars for data related tasks changed my life. Code remained similar in syntax but the systems became more performant at extracting efficiency out of the same machine.

Using connectorx for interfacing with the postgres servers was also a gamechanging moment instead of the OG pd.read_sql_query.

Across both of these minor changes, on moderate to large datasets, we achieved a near 10x improvement in querying data + doing operations on them.