Put a COD player on BF, He'll get ownd.
Put a COD player on COD, He'll get a 23 kill streak and get killed.
Put a BF player on COD, He'll nuke it and just say "good game."
Put a BF player on BF, I'm not even going to explain it.
First Get Battlefield 3, then buy MW3 afterwards when the value decreases so when you play on MW3, The noobs can troll on you.