I have different personalities when I'm with different people. Does that make me fake? No. I just know how to act accordingly depending on the situation and the person. I might be quiet and shy to you, but to my best friends I'm the craziest person they've ever met.
Because not everyone around you deserves to know you more. They doesn't worth your time explaining who you truly are. At the end of the day they just gonna betray you anyway.