We usually take ourselves to be the sum of these thoughts, ideas, emotions and body sensations, but there is nothing solid to them. How can we claim to be our thoughts or opinions or emotions or body when they never stay the same?
Teachers often suggest considering your thoughts to be like clouds in the sky. Some are dark and stormy, some are beautiful and fat, while others are wispy and ethereal. Sometimes there are no clouds at all. No matter. Just like clouds in the sky, thoughts pass through your mind. And just like the sky, your mind can contain it all.