Yogi: When there is no disliking, the mind looks for a more obvious object like the sound of the sea; but after a while there is no meaning to it and it becomes boring.
Sayadaw: Watching a neutral object, you need to come back to the awareness. You need to know that the mind is free from suffering when watching a neutral object because the mind is balanced. Some understanding can arise when you maintain this equanimous state. Wisdom never comes when the mind is agitated.
It is a habit that the mind likes excitement because that object is more obvious, and that is why the mind looks for a more exciting object.
The mind is neutral when the object is without meaning – no meaning, no feeling. The mind can only feel when it gives meaning to the object.
You need to understand the nature of the object and the knowing mind. Then both the object and knowing mind become obvious.