Yeah, that's a big one. In one case I reproduced a bug that had been plaguing us for a decade but could never seem to reproduce when it happened to a customer.

Yeah, that's a big one. In one case I reproduced a bug that had been plaguing us for a decade but could never seem to reproduce when it happened to a customer. Then the lore came out that the original programmer had slapped it together over a weekend. It worked in the lab, and mostly worked in the field but failed sometimes in weird ways. Then engineering tried fixing it. They failed three times, so they decided to replace that feature. It took two years to replace that one feature and get it to work right. It didn't kill the company, because it was a less used feature, but it reduced trust in the marketplace so growth took a hit that let other take and keep the lead.