30 minutes with a stranger

There is a huge selection bias there. People who are very disagreeable and hard to talk to tend to not participate in such a thing. Of course the average participant was open to talk to somebody and connect.

Fair, but it's still interesting that people underestimate how much they will enjoy the conversation, even if it's with a random person on a bus who did not volunteer for an experiment.

The participants in the train study were essentially given a "job" to talk to strangers, which completely changes the mental framing.

People generally try to follow through on a job they promised to do. They'll try to make the best of it so they feel like they made a good decision accepting the job.

If the conversations go badly, they can easily rationalize it away with "I didn't want to talk to them anyway, but I didn't have a choice".

Many shy and socially anxious people do basically fine in public-facing jobs because of this phenomenon.