how much does the affinity counter actually change the chat?

bumped into him in the hallway and the opening immediately throws up a favorability counter that starts at a harsh negative number after he swears at me for the collision. before I keep going, does that number actually shape how he responds as it climbs, or is it more of a flavor thing sitting in the background? he's set up as a transfer student who fights a lot and keeps to himself, so I'm guessing low numbers mean pure hostility, just want to know if it's worth tracking closely or if the roleplay carries itself regardless.