1) You can have a really terrible day, a splitting headache, your partner has disowned you and your cat has scratched your face off - but, when you are 5 minutes into your lesson, your woes seem like a distant memory.
2) Rather than rinse the energy out of you, your students in fact fill you to the brim with it. Even troublesome students make you beam from ear to ear.
3) You understand that it's not just about teaching on a superficial level. Rather you go beyond the call of duty by giving more support, attention (even out of class) to your students in their moment of need.
4) We have all had lessons that flopped, me included. But after some close reflection on what went wrong, you have this burning inner desire to do better next time to give your students your 100%.
5) English (or any subject for that matter) is vital, methodology goes hand in hand, planning is a must, your mental approach essential... but despite all that, you understand you are in this profession because you really want to help people.