When we meditate, our spontaneous activity is constantly changing. We can have lots of thoughts, feel the meditation is chaotic, be restless, or it can be calm, we may fall asleep. At times, we will be dissatisfied with what happens in our spontaneous activity.
When climbing it is a bit the same. You never really know how it is going to be like. The path you have chosen may be more difficult than you had anticipated, you may find grips you can hold on to or you may discover an exceptional view. All this just happens, there is nothing you can do with it.
While the climber is challenged by a steep mountain or his weak muscles, in our meditation, we meet our inner limits. It often comes as a creeping feeling of dissatisfaction. We wish our meditation was a bit different, and we try to make it the way we want it to be. We concentrate a bit.
When the climber finds it difficult to get, it doesn´t help to get angry at the mountain or wish that he was much stronger. He just has to adapt to how it is and do what he can. In the meditation it is the same, we just have to let things be. Not try to take control or try to achieve something.
Easier said than done? Perhaps. Good luck!
Sounds a bit like coping with the challenge of living!