You should not make your partner feel unimportant.
John's girlfriend achieved an important accomplishment that she has been working towards today.
John wants to go to the bar.
John suggests that he and his girlfriend go to celebrate her accomplishment at the bar.
John doesn't celebrate his girlfriend's accomplishment and goes to the bar instead.
John's girlfriend feels that John cares about her life and accomplishments.
John's girlfriend feels like John doesn't value her at all.