The first person who talks to you isn't necessarily your new best friend.
You may want her to be your best friend. In fact, way back in seventh grade when you were sitting at a lunch table alone, knowing no one in that whole cafeteria full of laughing, seat-saving people, she may have seemed as if she could be such a person—as long as you ignored her bubbling enthusiasm for Wednesday's after-school "Coven Club." And so you invited her over to spend the night. Six months later, you realized you'd spent most of your junior-high experience hanging out in her room, chanting ineffective, creepy spells until you finally admitted to yourself that you two had nothing in common.
Twenty years later, when you are sitting at dinner at a yoga retreat alone, you need to remember this moment from the past, because the first person who talks to you may actually end up being your best friend—or she may be a total nutcase (and often she is; that is why she is talking to you; she's exhausted everybody else and is pouncing on you in hopes of a fresh start). Instead, wait for the second or third or fourth or 80th person—the one whose company you enjoy instead of the one whose company merely dulls that ancient fear in your soul of never making friends with anybody ever. Or, better yet, be the one who gets up and talks to that interesting-looking person also eating all by herself. She is waiting for you.