Alternatively: someone who "believes in life after college" spends so much time worrying about that, and planning for it, that he neglects to actually enjoy and make the most of life while at college.
His colleague, however, not bothering about what may or may not come, just gets on with things, enjoys the experience and does his lessons knowing that he's doing the best he can to experience what he has now.
People have a sense of time - of past, present and future. They cannot just do away with that sense of time.
An important part of being happy now is taking care of the future.
And time at college is a preparation time.