Comment by BeetleB

I'm an introvert and please don't include me in the tiny subset of introverts who consider this a perk.

There's a spectrum within introversion, and this sounds more on the edge of that spectrum.

Full disclaimer: I too originally had trouble with calling to order pizza. But in retrospect it wasn't introversion: I just wasn't used to initiating conversations with strangers on the phone. The solution was trivial: Script the "opening lines" before calling. After a few of these, it all became natural.