The Buddha said that if you practice lovingkindness, or metta, meditation, you will experience scores of benefits (well, 11 specific ones). His list did not mention that you will have a better time at parties. Add that.
In the version of the Four Immeasurables practices that I do, you work with three people for each one: Someone you love, someone who irritates you, someone you don't really notice and have to cast around to bring into your meditation. Chances are these are the three types of people you will meet at a party (or really anywhere).
I like to get a head start. In the days before a social event, I bring people who are likely to be there into my meditation. Who will make my heart light up when I see them? That's the person I love. Who will make me sidle away from a group when they join? That's the irritating one. And who else was at last year's version of his party, standing next to someone who stands out in my memory? Oh, yeah. What's-his-name.
One by one, I offer them the aspirations of lovingkindness: May you be happy. May you be safe. May you be healthy. May you live with ease.
And a warmth develops -- toward all of them. The irritating person just wants to be happy. In fact, they are not irritating. I am irritated.That background person is also a human, with things that make her happy or sad. I wonder what they are? Maybe I will ask.
And extending the wish to everyone in the city, on the continent, on the planet. May we all be free from fear and know the happiness that brings.
When you get to the actual event, you will feel warm-hearted and curious, open and attentive. You will have a pleasant expression on your face, and people will be happy to see you. You will be happy to see them. Heck, devas will love you.
And if there are moments where that's not the case, you can stealthily emanate lovingkindness, silently making the wishes as you gaze around the room. Or extend it to yourself and leave, if it's that bad. Kindly, attentively, gently.
May you be happy. And may your days be merry and bright.