It is, of course, to the advantage of the store that you don't go directly to the one item you want. A lot of research goes into how customers wander through stores, and how to sell to them in that time.

http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5702...

http://knowledge.wharton.upenn.edu/papers/1293.pdf

http://www.bankrate.com/brm/news/advice/19990402c.asp