That's something an extrovert would say :)

Strong words. I'd like to understand your choice of words here.

> Categorizing yourself

Also known as knowing yourself, your strengths, and your weaknesses.

> purposefully stunt your growth

A wild assumption that talking to everyone will magically let you grow. Some people just prefer to focus on people that matter to them.

> ... reduce opportunity for growth

By choosing to compete in an area that is your weakness, you already limited your growth potential.

> ... wasteful use of life

So refusing to talk to everyone is a wasteful use of life. Again, I find it more wasteful to talk to anyone instead of people who matter to me. Unless it's fun, of course.