Small talk! I prefer to just chat to someone if sat by them, though usually need to kind of gauge how they'll be beforehand. I've said hello before to an awkward look away, but then, like on my train back from Cardiff one day, I was sat chatting to this guy for like 3 hours, he was really nice! And just said 'ta ra' when his stop came up. So, I'd rather make small talk than sit in silence, but I guess it does kind of depend on the atmosphere and where I am. I feel people are more open to chat and stuff up North for instance.