short term happiness

Many do not believe in an 'unconscious', and I think of myself as one of them. Yet today I realized that my mind very frequently fetched towards objects that I otherwise pay no attention to and gave the 'unconscious mind' some thought. This last week is the culmination of two months of GRE-studying, grad school searching, attending lectures, and working. I'm writing the gre this Thursday, I have a book review due tomorrow, and I have two important tasks at work along with trying to find a position that extends past my contract end date of November 11th. Yet, mind has settled on a material good I neither need (that much) nor have ever really thought about before. I feel ashamed to even write it out, but I'll say it quick and move on and so it's a Macbook Air, and I do not understand why my mind keeps returning to it. Mostly, I justify to myself why I deserve to buy this...object..and why I need it so much, why it's a good investment, etc. It's a huge preoccupation when I should really be focusing on the important things. Why is the mind so uncontrollable at times and what are the reasons behind it? There are emotional links to topics like love, hatred, etc, yet the mind sometimes settles on plastic products that otherwise have no sufficient value.