One of the parents who attended my recent class get-together remarked that it was hard for her just to listen when she goes to a concert. Oh! The MuzApp devils have truly taken their toll! Where else would she have gotten the idea that she had to be doing something besides just listening?
All it takes to listen is that one relinquish control over time. Think about it: It means whatever timing you walked in with you will let go of as soon as the music begins. If it is Adagio and you are a distinctly Allegro con brio type this will not be easy. (It never was for me; I used to hate having to listen to anything slow.) Just doing that, though I do not mean to imply that that is a simple thing to do, but doing that will allow you into the realm of the vibrations that the performers are producing and you will be more likely to listen.
Of course, that assumes that the performers are themselves paying appropriate attention, which is not always the case. I would go so far as to say that if you are bored they are bored.