It’s been my experience that project teams are simply made by allocating personnel from each function that have less responsibilities with other projects. Sometimes, people with some expertise or knowledge necessary for the project are pulled in, regardless of their schedules/responsibilities, but generally I have never seen teams being formed based on how well the members get along. That being said, I have seen conflicts arise within teams, but they were inevitable given that the people that began them did not get along with most people. As has been stated, teams are usually not made based on personal relationships because it is expected that everyone is professional and will do their job well, regardless of who they work with.