In
The Way of the Wizard, Deepak Chopra talks about viewing who you are now, and everything you do, as if it were a role you were playing, a character you choose to embody.
Right now, you are outgoing. You are also rich/poor, old/young, happy/sad, angry/calm, whatever. But that's not YOU. That's just the character you're playing right now. At any moment -- at THIS moment, if you want -- you can put that character down and play a new one. Maybe your new one will be outgoing and happy instead of outgoing and sad. Maybe you'll choose to experiment with playing a shy character. But remember always that it's the character. It's not you.
That's how I think of it, when I find myself getting too attached to my past and my emotions.