Being is interested is more important than interesting.
Both have different directions. Interesting is a short term pleasure by anything in our mind. It gives pleasure when it is happening but in contrast to being interested is much more important. Being interested we are living to do it again and again. It zeal does not allow us to sleep. It creates a passion, zeal,inspirations and all other things which convince us to do same thing more and more.
For example , Edhi Sahib’s Mother asked him to pay one paisa to the needy people. it was interested for a short while but when he was himself interested to help the humankind this zeal did not allow him to sleep. It kept him on continuous effort without any vocation. He attached in this interest till to death. It was due to being interested. If he sees to help the poor is interesting and once he follow being interested, he worked even his mother passed away. This is being interested.