I think it is somewhat logical, a person gets more tired as the week goes on. Of course, not all surgeons perform surgery every day of the week. Garramone only does it twice (sometimes 3 times), per week. There are too many variables for there to be a way to know if your personal surgeon will be tired on your day of the surgery. Maybe on Wednesday nights your surgeon stays up all night playing poker with the guys, so he is a crappy surgeon every Thursday. Since he is tired when he gets home on Thursday, he goes to bed early. Subsequently, he is extra rested before your surgery on Friday! There really is no way to know.
I personally would just keep the date. But, if it is really in your head there is no downside to asking to change the date. You will already feel some anxiety about your surgery on that day, no need to add to it.