I often talk about the fundamental difference between short and long term decisions and why it is so hard to make the long ones – like skipping the delicious dessert now to achieve health goals later or like giving up some of your paycheck now for a comfortable retirement later.
One of the primary reasons for this dissociation is that there are different brain modules that make the decisions. Your amygdala has a strong influence on what you do now, and your amygdala codes for emotion. So the taste of the chocolate cake or the desire to blow your paycheck on a night on the town evokes a pleasure reaction from the amygdala that we find hard to suppress. The long term thinking in the prefrontal cortex just can’t compete.
So I was reading a paper that brought a new dimension to this process. They claimed that there is enough psychological distance between us and our future selves that we don’t really trust them. What if we give up dessert now and that son of a gun blows it by eating lots of dessert later? He has all the fun and we still don’t achieve that health goal. That would really suck!! And since we can’t trust him, we are really better off just eating the chocolate cake now.
So your worst enemy is your future self. Or at least your conception of him/her.