Some thrillers have characters who make massive assumptions, huge leaps of logic... and by cinematic good will, they just happen to be right. Characters suddenly and inexplicably figure out who the killer is only when it's ultimately crucial, or they remember they had a knife in their pocket that's been there for such a long time you'd think they'd have at least accidentally figured it out before that perfect moment. Blood Simple is not that kind of thriller. It's the kind of thriller where characters make extreme assumptions, as people do, and invariably... they're wrong. This is just part of why Blood Simple is a great movie.