Multiple personality disorder?

My sister has to be the most observant person I know. There isn't a thing that pass her by and when you least expect it, she points something out that is completely true which you yourself never thought about. Like yesterday, we were hanging out and all of a sudden she tells me that I have several different personalities, this is her conclusion:
* chic and bitchy Sandra - the one that dresses nice, listens to the latest music, use English slang in everyday language, and, of course, have the ability to stare people down in the bitchiest of ways.
* geeky Sandra - the one that goes to Sci-fi-Fantasy bookstores, snorts when she laughs, and knows imdb pretty much by heart.
* academic Sandra - the one that loves school, books, and culture in general.
* rock Sandra - the one who lives for rock music, dresses in black, and gets tattoos.
* baby Sandra - ´the one who gets very sweet and cuddly from time to time.

I'm not quite sure what to make of all this except I guess it's good I'm far from being a one-dimensional human being. It would be fun if anyone that's reading and knows me could add another Sandra to the list. Just to see how many different sides there can be without me actually imploding one day, haha.