Spengler: There’s something very important I forgot to tell you. Venkman: What? Spengler: Don’t cross the streams. Venkman: Why? Spengler: It would be bad. Venkman: I’m fuzzy on the whole good/bad thing. What do you mean, “bad”? Spengler: Try to imagine all life as you know it stopping instantaneously and every molecule in your body [...]