There is a realism and practicality to the Islanders’ collective attitude that is surprising in its simplicity. With all the available extra motivation lying around a team picked to go nowhere and now proving almost all of the pundits wrong, never once has this group of young and inexperienced players — and coaching staff — patted itself on the back for overachieving. Instead of playing the underdog card, or the disrespected card, or the salary-cap-floor card, they just kept their heads down and worked hard and trotted out all the old clichés one day after the next. And what they’ve got on their hands now is a first-round playoff series where they are consistently outplaying the top-seeded Penguins at even strength, and aren’t about to make any apologies for it. They’re down 2-1 in this best-of-seven contest going into tonight’s Game 4 at the Coliseum, and the fact no one expected them to be there couldn’t be any more irrelevant. “We believed in ourselves going into the series that we could do the job,” forward Josh Bailey said. “We weren’t too concerned what everyone else was thinking outside the room. From the start of the year forward, no one really gave us a shot at anything.” Bailey says it with not even a touch of snarl in his voice, but rather a quiet calm that exemplifies this team. The 23-year-old who was chosen No. 9 overall in the 2008 draft has been one of the team’s best forwards down the stretch, and was elevated to the first line with John Tavares and Brad Boyes before Game 2.