To dream of an accordion represents making others feel that you are trying too hard or overcompensating. You or someone else that is putting too much effort into something. An accordion may reflect a failed attempt to impress or convince someone. Positively, an accordion may symbolize your attempt to show someone how hard you are trying.
Example: A young man dreamed of playing an accordion to his ex-girlfriend. In real life he couldn’t convince her to come back to him. He felt that nothing he said or did could impress her. The accordion reflected his attempt to make her feel like he was trying as hard as he could to impress her.