Broadly, this is a table-agreement thing. However, you begin with a false premise. If the characters are created with basically getting along in mind, folks can be cohesive without anyone "repressing" anything.
My players are informed before play begins that I run a largely cooperative table, and characters should be created accordingly. Characters who are apt to be disruptive, antagonizing, or duplicitous to their teammates don't make it to the table in the first place, so those things don't need to be repressed in play.
Yes, this does put a bit of a limit on the players to start with.