There are some people that no matter where you are when you see them or how hellish the day, they make all things better. It's as if they are a little reprieve from the world.
To me, that is the very essence of charisma. If someone can make you feel better just by the mere thought of them, they have it. That is the true charismatic litmus test. If you can do that, you have it. In spades.
One more thing about charisma. I find that most who think they have it usually don't. And loudness or brashness or look-at-me antics don't cut it either.
Often, it is the quieter ones that have it. Like a special elixer they were gifted with and share with the rest of us every once in a while.
Yes, they make every day a lovely day.