[Nyororin]

Do you know these people? Are you part of their social group? Do you say hello or just jump into the conversation?

If I were on the bus, talking about something with friends and some random person just contributed to the conversation out of the blue... I would be a bit stunned and wouldn`t really know how to react. It would be an uncomfortable situation, to say the least.

Try saying hello, introducing yourself, etc, first.