Too much LAG. Opponents TURNING OFF THEIR INTERNET/WI-FI temporarily and intentionallly to cause lag specially during crucial moments of the match or when not in possesion of the ball. UNFAIR plus-minus of points in online matches (you gain so little points by winning and lose so much when losing/drawing). INTENTIONAL NULL tactics by other players. HORRENDOUS and UNREADABLE usernames. Frequent server errors. SIGNABLE MANAGERS are always the same.