The tournament in Poland and Ukraine will be Sweden's first championship with Hamren at the helm. He succeeded Lars Lagerback who resigned after Sweden missed out on qualifying for the 2010 World Cup and knows he has a tough task ahead.
Hamren told Reuters: "If you have to be realistic England and France should progress from this group, but why the hell do you have to be realistic?
"If we had been realistic we wouldn't have beaten Netherlands in the final game of qualifying to progress to the finals either."
"Especially in the first match the host nation is usually tough to beat. Sporting-wise the sides are very even but now they have an entire nation behind them. It will be a difficult but very exciting match," Hamren forecast.
"They have more players to choose from so we must be better at other things, like teamwork and team spirit"
Hamren uses the melancholy and pessimistic donkey from A.A. Milne's classic children's book Winnie the Pooh to explain what kind of mentality is needed for Sweden to be successful.
"I talk about Eeyore with my players. If we want to have success we can't have any Eeyores in our team. Eeyore is not a winner, he's a really good friend, and you need them too, but not to play in our national team."
Sweden's stand-out player is AC Milan's Zlatan Ibrahimovic, top scorer in Italy's Serie A, but Hamren said: "The team is the most important player.
"We need the first 11 and the whole squad at their best and when we play with energy, courage and good organisation we can beat any team."
"Yes, Sweden! Of course we dream of being the Denmark of 1992 or Greece of 2004. That dream is the same for all the players and countries and that is what is so great about football - sometimes the most realistic thing doesn't happen."
