Forming is the stage in which, everybody in the team is polite and supportive. Some team members are anxious about what exactly their team is going to achieve, some are just happy to be there. Usually, this stage lasts for a while, as they make an effort to get to know each other and start to understand one another.
Storming is the stage where team members start to challenge the boundaries set in the forming stage. They challenge one another, conflicts may arise regarding different working styles, unexpected problems or just frustrations