Psychologists and economists love to talk about the notion of two selves: present self and future self. It's a nice way to explain the tendency to have one preference about the future, but a very different preference when the future becomes the present.
Let's face it: the present self is present. It's in control. It's in power right now. It has these strong, heroic arms that can lift doughnuts into your mouth. And the future self is not even around. It's off in the future. It's weak. It doesn't even have a lawyer present.
One of the primary reasons why the human brain has evolved to look so far into the future is so that we can take actions in the present that will bring us to a better future rather than a worse one.