I used to obsess over victories in some of the earlier Battlefields. I don't remember if there was a large payout to winning or not, but you could switch teams in BF3 which was heavily abused (by me too, fuck some of those teams).
Nowadays I care less about the victories and more about my performance, which may be less of a team player, but teams are generally less coherent than they used to be. If I have a reliable medic on hand I'll follow them into hell, but I generally pick my fights (assault positions, avoid tanks when I'm Assault, hold a position if I expect a counterattack, etc.) and ignore the attrition. I've saved a few games from defeat and I've probably lost more from not blindly running into the killzone as much, but I don't get bent out of shape when we lose since there's no longer any incentive to be upset.