Given him my approach in STAR format on how I implemented incremental ETL data pipeline and reduced the warehouse cost by approximately 50% vs how it was earlier executing on complete dataset. Conclusion : Weird enough, he was not convinced. Kept asking me If I'm sure that it was reduced by 50%, Either he doesn't know well about Data engineering or System design assuming he comes from Business Intelligence background. Its something that is unbelievable for him. Although, I confidently told him that I did reduce it by Approximately 50%.