> If you were in a bookstore and you said, “I’m done,” you’d walk out. If you were in a coffee shop and said, “This is boring,” you’d walk out. > You’re sitting at a party, and you decide, “I don’t like this; I don’t want to be here.” And then you don’t leave. Wait.. what?? Why would someone stick around at a party they don't like? Is this really what normally happens?
The reason was in the paragraphs leading up your excerpt: >, and so he decided that the unresolvability of the question was the answer. To the question “Do groups of people behave as aggregations of individuals or as a cohesive group?” Bion’s answer was that human groups are “hopelessly committed to both,” which is to say hopelessly committed to individual identity and to group membership.
Or put another way, the desire for social conformity can contradict private preferences.
If the bored person leaves early (fulfills a personal preference), he/she draws extra attention to himself because they're the only making an exit. This can also embarrass the host. So a reasonable rationalization is to avoid embarrassing the host (social conformity) and just suffer some temporary boredom.
But the above social calculation changes if multiple people decide to leave. Now, there's "safety in numbers" and leaving early is emotionally easier. Sure, the host still might be embarrassed but there's no longer a single party-goer to point disapproval at.
Another version of the above is clapping and standing ovations at presentations. If all the audience members expressed their true opinions, there might be 75% clapping and 25% not clapping. But polite society has an unspoken rule where everybody claps. Likewise when some think that clapping by itself is appropriate but a standing ovation is not. But then a few stand up ... and now everybody stands up.