In the realm of things you never every consider until it rears its ugly head: Handling SIGTERM of subprocess with in python popen. My god this is a nightmare. I solved some unexplained exceptions on shutdown that I hadn't been able to hunt down once I realized it had to do with a thread resource leak if the user hit ctrl-c while running a subprocess within a shelltastic contextlib block. I bet that doesn't make any sense to most people, but some people will read that in horror in feel.