Nobody can have the same charm for the same work all their life unless they are enlightened.
If you are enlightened, you can give the same intro talk a million times and still be so enthusiastic because you don’t live in the memory of it, you are living in the present. Or you are such a child who enjoys doing the same thing, and does not get bored at all.
That is why the word commitment has come to this planet. Don’t go only on whether you enjoy it or not or because you are charmed by it. You have to do it because you are committed to it.
In life we need to have both, commitment and charm. Charm gives you that little excitement now and then but commitment carries it on. Commitment will carry life forward.