Call of Duty Mentality:

Hurr I can killz 900 peoplez in 1 minute in a small map and get a kill-streak so I can nuke everyone. Who gives a fuck about my team as long as my K : D increases.

Battlefield Mentality:

I've got to use my head, work with my team, use my class perks, sacrifice myself to reveal enemy location, utilise vehicles and terrain, call for backup and use other techniques. I might not have the best K : D but I'll do what I can to help my team.