If you're taking advantage of post-holiday sales,  you'll want to hit the stores before noon to guarantee you make wise purchasing  decisions. Judgment and processing skills are at their sharpest in the morning,  which enables you to sort through all that merchandise and pick out what is best  for you. Plus, knowing there is more time left in the day means you won't feel  pressured to make a snap decision.

Source: Call of the Mall, by Paco  Underhill