I'd like to make a few suggestions to help keep games friendly :
Introduce yourself to the person that you are marking when there is a stoppage in play. Learn each others' names. This goes a long way toward breaking down the "Us vs Them" mentality.
Stifle the back talk. Even if you are amongst your team on the sideline, the other team can hear you
Try to resolve conflict early. It is OK to have a brief discussion about why something was or was not a foul with your counterpart, especially if both of you then go away with the same understanding. This is much better than continuing to be in conflict all game.
If you cannot have a friendly discussion about a conflicting call, between points talk to your captain, and let the captains come to a resolution. If one of the captains was involved in the conflict, the co-captain should be the one to meet with the opposing captain.
Finally, safety is paramount:
We all have to go to work tomorrow, and we all would like to remain uninjured.
Please keep it clean and contactless. If you cannot safely make a play on that disc, leave it be.
Sunset today is 8:03. Try to be early, and start your games by at least 6:30. At 7:45 captains should be agreeing on a point cap. If you can agree on your darkness plan before the game begins, all the better.