Slowness

Lack of Indexing: If your database tables are not properly indexed, queries can take longer to execute, especially for large datasets.

Inefficient Algorithms: Poorly optimized algorithms can lead to slow execution times, especially for large datasets. Choosing the right data structures and algorithms can significantly improve performance.

Ruby Version: Older versions of Ruby may lack performance optimizations and improvements available in newer versions.

Framework and Library Choices: Some Ruby gems and libraries may not be optimized for performance, leading to slower execution times. Choose well-maintained and widely-used libraries when possible.