I've been in situations where I was desperate enough to do it by hand. 20+ builds and manual tests later, I found a really nasty bug in some 3rd party code tha

I've been in situations where I was desperate enough to do it by hand. 20+ builds and manual tests later, I found a really nasty bug in some 3rd party code that manifested with the most bizarre repro that had no obvious connection even in hindsight, and symptoms involving cleanly exit(3)ing out of the program from a totally unrelated bit of code.