It's just a terrible game. The online is crap, the single player is crap, and then once you beat it and unlock custom clubs, you realize how much more crap it is. The create a player is also stupid as is the way you level up. Basically in the end everyone is maxed out with the same stats, and the way you level up is terrible as well and such a grind.
For instance, the way you level up a club's control stat is by landing on the green with that club. So in order to level up a driver's control, you have to land on the green. Think about how stupid that is.
And the whole "open world" thing is pointless and ads nothing. And in order to build custom clubs, you have to basically search the golf courses to find gems. And I think you can find like 10 or something a day, and it takes 120 gems to make a pair of custom clubs. Oh, and the custom clubs are all completely random as to what their stats are. Oh, and the clubs also break after not much usage, I think like 5-6 rounds, so you have to grind more gems again to build more. Oh, and if you don't feel like grinding, you can conveniently buy gems with real money.
There is a laundry list of why the game is terrible. You can google and read forums about it.
Yet, it has a 78% score on Metacritic.