Even my 4-year-old knows that it is always good to end on a high note. This age-old advice is a great philosophy to apply to your workout. If you spend the last few minutes of your workout doing something you enjoy, or something you are good at doing, I think your chances of returning to the gym will increase.
If stretching is pleasurable, end your workout with it. Accompany your favorite stretches with your favorite song and you might just have created a perfect moment. If your gym has a sauna or a steam room, take advantage of this relaxing perk. Ending each workout with something relaxing and pleasurable means the next time you think about exercising, you will think of those nice activities and not pull-ups (sorry for projecting).