One of the fastest ways to start a fight in a hockey game is to hit the goalie. The goalie is one of the most valuable players on the team. His team will always make sure that no one touches him. If anyone hits the goalie or tries to hit the goalie, someone on the goalie's team will rush to hit him.
Forwards will always try to get in front of the goalie to block him. This makes it harder for the goalie to see the incoming shot. The defenders will try to push the forwards away to keep them from blocking the goalie. The player with the puck will shoot and hope the goalie never sees the puck or it deflects off of someone so the goalie can't catch it.
The best way to practice hitting the small corners of the goal left open is with hockey targets. These targets have a plastic head, neck, and shoulders. This is to teach you how to shoot through someone in front of the goalie. Besides using hockey targets, there are hockey drills that help players train their shot power and accuracy. If they can increase their skill, it isn't as important to try to hit the goalie and risk getting in a fight or taking a penalty.