A study in the British Medical Journal says if you need an operation, don't schedule it for the end of the week.  

They analyzed 4 million planned surgeries and found the death rates were 44% higher on a Friday, and 82% higher on a weekend.  

They can't put their finger on why, only assuming that medical care "drops on the weekends."  No kidding.

Boils down to this:  Unless your appendix explodes and you have no choice, schedule your surgery for Monday.