I'm Really Not An Idiot...I Swear.

Why is that when I go into the grocery store, its like setting foot in a completely foreign land to me???? I consider myself relatively bright, well relatively. So why is it that as soon as I enter the front door of a grocery store I turn into an idiot?? Can't find things....end up going back and forth across the store, and of course being a man not like I'm going to ask for any assistance.....this phenomenon is just mind boggling.