"The person who loves walking, will walk further than the person who loves the destination"
There are 2 main things I've found to make the biggest difference when it comes to actually getting results in the gym:
Consistency over time
High Effort
So what does this have to do with enjoying your workouts?
More enjoyment = More consistency
We are more likely to repeat behaviours if they give us more positive outcomes than negative ones.
If every time you go to the gym you: feel intimidated, get frustrated and hate your workout then it's going to require a lot more willpower and motivation to turn up consistently.
Alternatively, if every time you go to the gym you: see friends, hit a new PB and leave with an endorphin rush then you are positively reinforcing the behaviour of going to the gym. Which will soon enough result in you actively wanting to go the gym rather than having to go to the gym.
Therefore by optimising for 'workout enjoyment', we can curate a workout experience that makes us less reliant on motivation and therefore more likely to turn up consistently.
More enjoyment = More Effort
How much effort do you put into something you resent? Usually... not much. How much effort do you put in to something you love? Usually... a lot.
In my anecdotal experience, those exercises which clients are more intrinsically motivated to progress are usually the exercises which they put more effort into and thus get better results with.
Whilst this is somewhat intuitive, there have been several studies which have linked job satisfaction to productivity. And, although it's not a direct comparison, I think there are some parallels from this that we can draw to exercise too.
More Consistency + More Effort = Better Results
Put simply, by prioritising the enjoyment of your workouts you're more likely to be consistent and you're more likely to put in more effort. These are two of the biggest factors affecting your gym progress, therefore the most 'optimal' training programme may in fact be the one you enjoy the most.