Can teaching be effective even without passion? Why (not)?

“I recall my most influential teacher – Mr Tomlinson was very strict in discipline, but he had a mission to leave no student behind. He worked hard (and made us too work hard) to ensure we not only knew what was in front of us, but know where we were going. Did he exhibit the usual manifestations of passion – probably not, but his passion was to impact on us. We must not confuse passion with excitement, ra-ra, or a particular method; but with a deep abiding commitment to change the learning lives of all students in a most positive manner” (John Hattie, personal communication, February 16, 2016).