Golf training has two main goals 

1. To achieve change in your body and mind. You can achieve that by pushing yourself into uncomfortable feelings and states, which "tell" your body and mind to adapt.

2. To maintain the current state if it has reached its maximum potential. Again, you need to demand 100% effort from your body and mind to maintain this maximum potential. Otherwise they will change back to a state that is sufficient for current demands.

To gain maximum benefit from a golf training session, you need to know the purpose of training and motivate yourself to push through the uncomfortable parts of the practice.

That's how to achieve the fastest and biggest change of your current state.

Motivation. Without it, the player will not push into these uncomfortable feelings/states and therefore will either not improve or improve at a very low rate.

That's why only players with very strong internal motivation become top players, since they were able to endure hours and hours of  training, which in the end made them  fit, mentally tough, masters of golf technique and strategy.