Depends on team of course. In my opinion 1-0 is more dangerous.. for example Inter vs. Real Madrid..
It's 5th minute and corner, Cambiasso took Inter to 1-0 leading position. Now imagine how hard Real Madrid is trying to make it 1-1..
Now imagine 2-0.. Real madrid's punch of stars are close to crying, ronaldo starts to dive, pepe doing pointless fauls. Reaaaaly dangerous...