The author of the text, Jared Wyatt, CTO of Matchbook, an app that uses MongoDB as its database, recounts how the app's performance issues were caused by a combination of factors including a redesign of the API and backend infrastructure. After the app was featured on Apple's home page, the user base exploded but also led to massive amounts of time being spent in the database during spikes of heavy activity, causing performance issues. Using MongoDB Monitoring Service (MMS) to track down the problem, they discovered that case-insensitive validations were running regular expressions instead of strings, leading to slow operations and high latency. By setting up MMS, monitoring their application's performance, and making adjustments, Matchbook was able to optimize its performance and fix the issues, ensuring a smooth user experience. The author emphasizes the importance of monitoring tools for small tech startups, highlighting the need for visibility into operations and data interpretation skills to optimize performance and solve problems efficiently.