Expanding on this advice: never assume that the libraries or programs you use are bug-free. Before digging deep into your own code, make sure the bug actually

Expanding on this advice: never assume that the libraries or programs you use are bug-free. Before digging deep into your own code, make sure the bug actually is in it, and not somewhere else. I have seen problems where a particular program didn't work, due to the other side - which I had nearly no information about - had a bad optimisation, which made it crash. Or another, recent case, where a particular third party library was abusing a cache, and stored freed objects in it, which resulted in interesting crashes all over the place.