I'm a snail with a shell that wants to be human.

I'm like a snail pulling quickly into its shell when its sense of touch detects that its skin has been touched by another skin.
I'm always on the alert, and the personal space I need to feel comfortable is quite vast. I like the wide and spacious nature. No people can touch me.
I'm a snail with a shell that wants to be human. Or a man who no longer wants to be a snail?