I frequently see folks fail to understand that when the unicorn rocketship spends a month and ten of their hundreds of engineers replacing their sharded mysql from setting ablaze daily due to overwhelming load, it is actually pretty close to the correct time for that work. Sure it may have been stressful, and customers may have been impacted, but it's a good problem to have. Conversely not having that problem maybe doesn't really mean anything at all, but there's a good chance it means you were solving these scaling problems prematurely.

It's a balancing act, but putting out the fires before they even begin is often the wrong approach. Often a little fire is good for growth.