I was out sick the day an urgent ETL job I was building would be due, so it got reassigned. When I return, I find most of my code commented out and replaced.

The first step was rewritten, with a comment that reads "Made changes to run faster." What used to be a single execution lasting 30 seconds was now a 4 step process taking 5 minutes, and yielding identical results.

Being a one-time execution (not a recurring job), I'm left wondering why they thought execution speed was even an issue, let alone what about their redesign they felt was an improvement...