LOL, be VERY afraid of something that "just starts up and works," is my motto.
I was recently working on something that "just ran," and would have been very easy to give a pass through to production and crack the champagne bottles...when in fact it was so out of balance the DC servo was just barely holding things together. The only evidence of this was a larger-than-average glitch when switching gain--nothing at all was apparent on the analyzer.
Or a new thing I'm working on now, which is much more complex than the average Schiit product, which similarly "just started up and ran." It was almost a relief when I found I'd reversed the polarity to the relay coils...specifically, to 10 very small SMD relays, to be exact. On a 4-layer board with the relay traces buried. Yeah. Argh.
Ha! Well at least with burned traces you have a very clear problem indicator.