I couldn't disagree more with Jayne, as it happens.
Passion, as a verb, is misplaced, overused and ultimately meaningless. How should a teacher demonstrate his or her passion? Let's be honest, no one wants to see teachers jumping on tables, ripping their blouses open and chest beating.
'Passion' means you care so very much about the children/subject that you will be malleable, open to whatever nonsense is flung your way and so on. That isn't passion, that's fear. Fear that either if you don't comply you'll be out of a job, or fear that if you don't comply the children won't reach their potential.
Either way, it's a poor thing to demand from somebody. We need teachers who are knowledgeable, skilled and have talent and heart, too of course, as we are working with children not machines. However, teachers are not one robotic body and having a narrow and fixed viewpoint that the only good teacher is a 'passionate' teacher means that many potentially excellent teachers may fall by the wayside.
I have known some teachers teach for a few years with panache, flair and yes, passion, and move on to other things. Teaching isn't a prison sentence and shouldn't be treated as such. I've never understood the view that teaching should be what someone wants to do at the expense of everything else. I knew an exceptional Geography teacher with a thirst for travel who freely admitted he chose the job for the holidays. More commonly, I've met many female teachers, I'm sorry to say, who went into teaching because it fit well around their own families. None of them were notably worse than the 'passionate' ones who went into it because of 'passion.'
I am concerned that this stereotype, much trotted out in different forms, is actually hugely detrimental to the profession as a whole. If we raise legitimate concerns about pay, why, we are in the wrong job. The inference is that if only we had the passion the pay would not matter. Similar to the OPs question about holidays - if she was only a bit more passionate her own children wouldn't matter and only the ones she teaches would.
Of course, that's clearly silly when it's written down like that. I will say quite openly I am not and never have been passionate. If a school wants a calm, reliable, level headed, skilled and talented teacher, I'm their woman. But passion? No. I'll leave that to the fruit.