I believe passion from a teacher can be easily seen from a student. Think about when you, as a student, started a new school year; I'm sure you had all the expectations in the world of how this school year, or class, will be so great. ESL/EFL students have these also...they want to have a really good, memorable experience. As for a teacher putting on a "show"...a teacher should bring to the class as much as he/she can. I try to show this in my class with teachers/potential teachers that a teacher has many qualities as an arsenal to captivate students attention to study more effectively...dancer, entertainer, singer, artist, storyteller, mentor, etc.