On the other hand, Sirius did understand people. He may not understand himself, but he was quick to pick up on lies, interest, and girls who weren't completely into their boyfriends. In fact, Sirius would much rather run around and try out all sorts of social interaction instead of do school work and study. Most of the time, that's exactly what he did. Sirius knew how to approach a stranger, and he also knew the best way to approach a girl he'd slighted.
"What's to say we can't cuddle on this blanket now? We could talk about strawberries or your favourite thing to do, since we already talked about mine." Sirius was also one of the less shy blokes at Hogwarts. He was blunt, and often got right to the point. Sirius hated beating around the bush and taking hours, seven dates, and countless minutes thinking about something that could have been solved within the first hour!