I am working on being more outgoing, but in general I have always been too shy to initiate conversations with strangers I see playing pinball. I love it when people come talk to me, though! The most successful conversation starter in my experience is when someone asks me something specific about a game, like a question about the rules. I find generic hey/how are you type stuff difficult to respond to, but rule questions always have an actual answer, so I think they're a great way to break the ice.