In last week’s Query Plans Pop Quiz, the first question was, someone hands you these two queries and you get their estimated plans to decide which query to tune. Perhaps you get the estimated plans from SSMS, or from sp_BlitzCache, or from your monitoring tool.
The question was, which query should you focus on tuning? A disturbing number of comments pointed at the top query, saying that it had 100% of the cost, and that its sort was 99% of that giant cost. Wrong-o. Not even close. Do not pass go, do not collect $200.
The right answer: ignore