I like the freedom that comes with travelling to a place where no one knows you.
I like the freedom that comes with travelling to a place where no one knows you or what you are usually like, and so they don't expect you to act the way they're used to. You can completely reinvent yourself-- just for a day, you could be a confident, outgoing person, and no one would bat an eye just because "ooh, the quiet one is dancing."
I like the feeling that comes with being among strangers. They haven't labeled you yet. They don't have a certain image of you in mind, they don't expect a certain behaviour from you. You can choose to be anyone. Or, you could finally start being yourself.
People continually grow and change. But when we know someone for a long time, there is a sort of resistance to them breaking out from the box we put them in. Supportive surprise is okay, but saying things like "huh, I didn't know you could talk," or "So what, you're a big-city person now? Our town is too small for you?" just forces them back into their shells.
I realised, when I went on vacation, that I was a much more confident person than I acted like at school. It's just that my classmates were used to one version of me... the shy, hidden-in-the-shadows me. And breaking out from that mould is what was scary. So, I didn't. I waited till school was over and I could go to College and re-introduce myself to a brand-new group of people.
We need to understand that people, especially those we've known for a long time, are not stagnant creatures. They can work on themselves and outgrow your perception of them. That change shouldn't be met with sarcasm, cynicism or ridicule.