Instant gratification means staying up too late playing Xbox before an 8:00 AM final exam, and jeopardizing your chances of walking in well rested, calm, and focused for success. I have found that I took the instant gratification path when I feel like I hadn't done my best work throughout the semester.
Long-term success include making plans to celebrate in a big way once your finals and juries are completely done, but in the mean time, choosing to work really hard reviewing what you have already learned in your courses this semester, eating well, staying hydrated, getting plenty of sleep, and reducing stress by taking short breaks from studying by walking around campus, taking care of menial tasks on your to-do lists, etc.
Which path will you choose? Choose wisely, and good luck on your exams!!!