Friends will show offline and you have no way to send an invite.
Servers lag often.
Sometimes people cant hear each other half way through the game.
Hitmarkers show a delay when veiwing killcam even on a good internet line.
Your own footsteps will sound asif in your head and will drumm basicly out all over sound.
Other peoples footsteps if you are so lucky as to hear them will sound 5 meters away from you but you wont know if they are above or below you!
and then every month a new updates comes out to give you a new list of problems!
Snipe shots are rewarding and when the game runs its fun to play!