TAMPA — This is the third time in four seasons that the Lightning has reached the Eastern Conference final. The one year it didn't was last year.And last year could turn out to be the best thing that has happened to the Lightning and its coach, Jon Cooper.Last year's playoff-missing hiccup was a good reason to clear out some veterans to make room for young stars such as Brayden Point and Yanni Gourde.It made the massive move to part ways with goalie Ben Bishop in order to hand the No. 1 job to Andrei Vasilevskiy.And other roster tinkering was done that has helped the Lightning once again become one of the NHL's elite teams.But something else happened that has had a critical impact. Instead of coaching in the Stanley Cup playoffs, Cooper coached Canada in the World Championship, a tournament held during the playoffs that often involves NHL players whose teams are not in the postseason."It helped me immensely," Cooper said. "I can … say my experience in the World Cup in 2016 as an assistant, just kind of being around the other coaches then, how things are done (helped). But to be able to run your own show when you go to Worlds, surround yourself with (other coaches) … it was amazing for me."For Cooper, not only did it help being around other coaches, but being around world-class players was a teaching tool, too. He coached stars such as Winnipeg's Mark Scheifele, Colorado's Nathan MacKinnon and Philadelphia's Claude Giroux."You go down the list, you learn from those guys," Cooper said. "It was a wonderful experience."He also got a first-hand look at how a young player from his NHL team handled the intensity of big games. Point had four goals in 10 games in last year's Worlds, and Cooper's Canadian team nearly won the championship. The Canadians, who also featured the Lightning's Alex Killorn, lost to Sweden 2-1 in a shootout in the gold-medal game. One of Sweden's stars was Lightning defenseman Victor Hedman.Meantime, know which goalie was selected as the best of the tournament? Vasilevskiy for Russia.Turns out the World Championship was a great experience for plenty of Lightning stars.But none more so that Cooper."When I came back from Worlds, I know I'd taken a step in my coaching career," Cooper said. "I think that has helped. Whatever has happened since then, it's really propelled me to be better."It certainly has worked this season as Cooper got the Lightning back to the conference final as he eyes his first Stanley Cup.Hard to believe, but Cooper, hired by the Lightning in March 2013, is the second-longest-tenured coach in the NHL. Only Joel Quenneville, who just wrapped up his 10th season with the Blackhawks, has been with his team longer.With the way Tampa Bay is playing, Cooper isn't going anywhere soon.And if the team keeps playing like it is this season, Cooper won't be back coaching in the World Championship, either.He'll be too busy coaching in the playoffs.