A four-hour delay can turn a gate full of strangers into a team. Shared trouble is a fast introduction.

Nothing dissolves formality like a common problem. Fifty people who would not have spoken start comparing information, holding places in queues and sharing chargers, because the usual reasons to keep to yourself stop applying when everybody is equally stuck. It does not take long, and it needs nothing in common beyond the situation.

When the next thing goes wrong in public, say something to whoever is nearest rather than retreating into your phone. A delayed bus, a power cut, a queue that is not moving. Those are the easiest conversations available, since the opening line is already there.