Several of the teams I worked with identified specific circumstances which would trigger a Kaizen event (Continuous Improvement Meeting). These triggers included one particularly dire situation: releasing a priority-one bug to production. If this happened, they would fix the problem immediately. Fortunately, they had a deployment strategy that meant they could usually quickly recover if they couldn't isolate the problem straight away.
Inspired by a ThoughtWorks blog post, https://www.thoughtworks.com/insights/blog/make-failure-taste-better-failure-cake, they would then buy a cake for everyone and invite them to a meeting. While eating the cake, they'd perform a root cause analysis to determine what went wrong in their process and how they could prevent it ever happening again. The purchase and eating of the cake was deliberate; it was intended to give the team space to reflect and also encourage others involved in the incident to attend and give feedback. As a result of following this process, they very rarely released any priority-one bugs into production.
Here's a real example of one of our teams reflecting on how to improve their process using the Five Whys method.