The Buddha says there's a different way to approach the whole issue of happiness, so you don't have to be afraid of other people, and you find that you can actually be more compassionate to them.

"Now the Buddha doesn’t say to ignore other people and just be very selfish. He says there’s a different way to approach the whole issue of happiness. In other words, you find a source for happiness that doesn’t take anything away from anyone else, so you don’t have to be afraid of other people. When you’re not afraid of them, you find that you can actually be more compassionate to them. So developing and maintaining this center inside is not a selfish thing. The Buddha’s not teaching you to be insensitive. He’s just saying to put yourself in a stronger position and to trust that you’re stronger by not trying to go outside and fix up people’s moods and all the other things that we think we can do with other people when we’re dealing with them. Just stay inside and have a sense of confidence that you’re strong inside. After all, your source of happiness lies inside. Because it’s not taking anything away from anybody else, you don’t have to be afraid of them.

Especially when you can get your awareness to fill the whole body, when you get the breath flowing smoothly throughout the whole body: This smooth flow of energy builds up a kind of force field. An image in the Canon is that the meditator who’s able to fill the body with awareness is like a door made out of solid wood. If you were to take a ball of string and throw it at the door, it wouldn’t make any dent in the door at all. The mind filled with awareness, with the breath energy flowing smoothly, is the same sort of thing. It’s solid. It resists outside influences.

But when your awareness doesn’t fill the body like this, the Buddha says it’s like a ball of wet clay into which somebody throws a stone. The stone makes a big dent in the clay. In other words, you’re in a weak position, and you intuitively know you’re in a weak position. Other people can invade your inner space. So you scramble around and try to build up all sorts of defenses. Because so much energy gets spent in the defenses, and the energy is outside the body, it knocks you off balance. You use up the water of your meditation, the refreshment of your meditation, very quickly this way.

The trick, as Ajaan Lee says, is to have a little distillery in the boat so that you can take the salt water and put it into the distillery, to turn it into fresh water. Then everywhere you go you’ve got fresh water. In other words, no matter where you go, you’re right here: centered in the body, with your awareness filling the body. You’re not leaving the body unprotected and you’re not using up all your energy in those false outside defenses. You’re creating a sense of energy here in the body, a sense of refreshment, and it’s protecting you as well. This way you can travel around the world because there’s salt water everywhere. If you’ve got the skill, you can turn it into fresh water — as much fresh water as you want."

~ Thanissaro Bhikkhu "Social Anxiety" (Meditations3)