[mtlmtlmtlmtl]

I'm aware you can get some pretty crazy behaviours, say if you end up overwriting a return address and your code begins to jump around like crazy. Even that could reproduce the same behaviour consistently though.

I once had a bug like that in a piece of AVR C code where the stack corruption would happen in the same place every time and the code would pathologically jump to the same places in the same order every time. It's worth noting though that when there's an OS, usually what will happen is just a SIGABRT. See the OpenBSD libc allocator for a masterclass in making misbehaving programs crash.

I was never advocating to rely on UB, btw. But yes, UB can be understood in many cases.