For most people, parties are difficult. Just meeting one person socially is difficult. It involves listening and talking to them, often without an agreed topic of conversation, while trying to improve their opinion of you, usually with it implied that you’re not thinking about any of these things. All should seem natural and easy. With close friends it is easy, of course, because you know more about them, which makes it easier to think of things to say. Nor do you need to worry so much about being liked.
This is why a pause in conversation feels so uncomfortable. At such moments, the fact that you are struggling for things to say to each other becomes too obvious to ignore. This loudly implies that you are not close friends or, conversely, that your opinions of one another matter so much that it impedes your thinking, perhaps because you find each other attractive. All of which makes it still more important to think quickly, in order not to leave pauses.
To this mixture of difficulties a party adds the element of display. At a party you are required to perform the same difficult social tasks, but you must do them repeatedly and in public. In this way, parties make you aware of your place in society. Perhaps you are made aware of your failure, because you don’t know anyone, or because you find conversation difficult, or because you are very worried about what others think of you. You can even fail by lacking the courage to attend, or by not being invited. On the other hand you may thrive, because you feel well known and liked. Parties publish your social performance for everybody including yourself to see, so the stakes are high.
Indeed it is the purpose of parties to make socialising both more difficult and more important, in order to provide a test. A party is elite-level socialising, the event for which the rest of your life is training. This truth gets hidden because of course not finding parties difficult is the measure of one’s success in them, so people are reluctant to admit it.