Expectation
Experiences and pictures are no one mije dve meditation practice. What is important is your mind development. All experience is just natural consequences of your practice. Without expectation your mind can be stilled easier.
Expectation is always accompanied by worrying. We spend more of our mind energy when we expect things. One right solution is to just be mindful. It means if you can be careful and calm at the same time, you will have the best conditions for your mind to be still. Never let stress stay in our mind. With calmness your mind spends less energy.
