Pre-purchase, the customers are just looking at lists of features. Post-purchase, they realize the ovens burn bread and cake 10% of the time and pizza 100% of the time, and they just want a good working oven that doesn't burn food.

It seems like most customers are returning the oven, which would normally be an extremely strong signal that there is a quality problem. In the SaaS world, the equivalent would be churn, but it's not always as straightforward since if users quit before they sign up (e.g. by reading a review or using a free trial), then they don't show up in that metric.