The worst part happens before anyone speaks
Your thumb is over the button and your brain is listing reasons not to press it. They will not want to talk to me. I will not know what to say. It will be awkward, and it will be my fault. Nearly everybody has this voice, and it is remarkably consistent about what it fears.
It is also, remarkably consistently, wrong. In 2021 the psychologists Gillian Sandstrom and Erica Boothby pulled together several of their own studies into a mini meta-analysis titled, plainly, Why do people avoid talking to strangers? (published in Self and Identity). People worried that they would not enjoy the conversation, that the other person would not like them, and that they lacked the skill to keep it going. When they actually talked to someone, all three fears turned out to be overblown. The anticipation was the hard part. The conversation was fine.