Allowing your week to revolve around one event generally isnt a good idea. If that one event turns sour, so does your week. When you are on a diet, your weigh-in can become that one event. If your diet is important to you, then your weigh-in will also be very important to you. A weigh-in will give you thumbs up, thumbs down or hanging on; it is your weekly progress report.
I used to feel elated when I got a thumbs up, and dejected when I got a thumbs down. Sometimes those feelings would last all week until the next weigh-in, which would either confirm the feeling or change it. Please dont make it this way for you. The weigh-in gives you feedback, and feedback is extremely important. Treat it as information and stay off the emotional roller coaster.
What can you do to help yourself just before you step on the scale? Do you have any last requests? Is there anything else you can do to increase your probability of success? If you are thinking about taking fast-acting laxatives, Ill give you a few bonus points for thinking outside of the box, but please do not rely on such substances. I certainly wouldnt want to compound my problems by getting addicted to something...