If something can go wrong, no matter how small this possibility, it will always happen.
First, anything not surface looks so simple;
Second, everything will be longer than you anticipated time;
three things wrong will go wrong will go wrong;
Fourth, if you are worried about a situation occurs, then it will occur.
After the overall goal set a target multiple stages to complete a goal, the equivalent of one thing OVER. Toward the next re-adjust after a goal, and that will always achieved initial success, but will not be Murphy's Law will spend, good psychological expected to take longer, but it would certainly made the most of a victory target