This game can be great sometimes, you can be playing ultimate team, and everything just flows, your players pass where you tell them, strikers make runs, you can score some great goals. Often you will comfortably beat a guy by simply outplaying them over and over, and it feels great, and makes it want to play more and more games.
But then there is the ugly side of it all, moments that make you enraged, frustrated and helpless. Some examples would be, my Keylor Navas completely missing the ball for a clearance, allowing a striker to nip in and get a goal out of nothing, and at the same time I was blameless. Or my Varane needlessly conceding a corner when he could have let the ball go out, but insists on trying to keep it in. The resulting corner then leading to a goal, which is once again, completely not my fault. If you AI wasn't so braindead, Varane would have let the ball go out for a goal kick, or the game could have let me pull him back to prevent it, but no, I have to endure it.
Other moments when your opponents goalkeeper plays out of his skin, when you have all the possession, shots, pass accuracy, but you can't win the game because the random factor in the game has decided that this guy's goalkeeper will be a god today, even though he doesn't deserve it the way he is playing. Or when your players lose every 50/50 challenge/aerial in the middle of the park, leading to extra chances for the other team.
My point is, there are far too many random factors in Fifa for it to be enjoyable and fair like most other games are. This game will never be truly competitive compared to the likes of LoL, CS:GO, CoD etc.