
In the centuries upon centuries that humans have interacted with horses, we have come around in our thinking, progressing further with ethical treatment and understanding of the abilities and attributes of horses.
Our interactions in terms of partnership can be seen across a continuum of flavours. The representation above, shows three simple categories. We might say that a racehorse would be in the leftmost category for the most part of their interactions with humans, having one option and no choice in their activities (debate could uphold that horses inherently like to race – in which case would move the partnership towards the middle category where they are conditioned to make this choice).
Many pleasure horse activities operate in the middle ground, where the horse is not given a free choice in the matter, but will receive training to motivate them to choose the activities that we would like them to do. Even liberty work will often involve pressure, bribery, or some kind of influence over the horse to act in a particular way that the human wants.
Motivating a horse to choose from limited options is founded specifically on one premise – disrupting the horse and then allowing the horse to seek comfort. In this context we cannot systematically judge a positive reward as kinder than a pressure based motivator. Once conditioned to a positive reward system, the horse knows that they cannot get the food (the source of their comfort) until they have pleased you. Therefore, their normal patterns of accessing food when they choose have been disrupted and the horse will have some level of anxiety until rewarded. This is why nibbling, impatience, and nickering often come into play during positive reward sessions. Those behaviours can also be managed, but as soon as we shut-down a behaviour, we are not empowering the horse in interacting with us which is something to keep in the back of ones mind.
Not everyone aspires to a pure partnership. Humans are invariably, a controlling species. However, we can add doses of empowered interaction into our typical “dictated” or “controlled choice” partnership.
For ideas, Elsa Sinclair is the guru in this area. Here are some of my tips for creating interactions where the horse can feel empowered:

Greet your horse in the paddock with no human agenda, carefully observing their body language as you move in closer, allowing them to accept you (or reject you) within their personal space. When you are close, hold out an outstretched hand, allowing them to sniff you as long as needed.

Allow your horse to be curious. If you are in the middle of something, give them a bit of time to check out something, sniff some poop, or look at something far away.
Let them decompress now and again. Recognise that whatever you are asking of them, no matter how low pressure or positively reinforced, produces anxiety as they are not fully empowered to do as they please.
A waiting break (count out 20 to 60 seconds), gives the horse a chance to let out some tension. Don’t interrupt their calming signals – give them a chance to process things on their own time.

Encourage them to roll, find some relaxing pressure points on their body, or just stand beside them taking deep breaths and listening to the sounds of wherever you may be.

Once you have established a bond of mutuality, your horse might be willing to initiate play with you. A game that I have played with my horse is to move in reaction to their movement. It could be in sync or opposite, away or toward, lift an arm, or any type of non-threatening action. When the horse does the same action, repeat the same reaction (this can be a time consuming activity!). When the horse realises that they are controlling your actions, they are often quite relieved and show a release of tension.
Building these little empowering interactions into your sessions with your horse will make you more pleasant as someone to hang out with and you may start to find more free choice and playful coordination appearing in your encounters.