Why is a two goal lead considered the most dangerous lead in a game of hockey?

It considered the most dangerouse lead in a game because it's more then enough to win easily, the opposition see a change to catch up (after 3 or 4 the opposition usually quites trying), finaly, the team with the lead may start to slack because they think they have the game in the bag (and 2 goals can be scored in less the two minutes to tie the game, then the momentume will be for the opposition)