Honestly though, was it definitely bad or just cooked weird? I've had cheap cuts come out tough and rubbery just from the slow cooker running too hot all day. That weird smell can sometimes be the bone or fat you don't usually get on pricier roasts. Maybe try it in the oven next time, low and slow with some broth.

Admit it, @ryan_scott36, my lunges are more predictable than my love life.