It's a very very hidden big irony.

He started the movie as a jerk and egotist, with everything in his mind being about him and not caring about others. At least, on a minor, 1-person scale. We are led to believe that this perception of things being about him are wrong.

Then, as we find out after the movie ends (see [wbogacz][1]'s excellent answer), the whole **universe** was frozen in thousands of days of a loop, **all for the express purpose of providing a lesson to Phil that his initial worldview is wrong**.

Except, in the end, it **is** all about Phil. The only mistake in the beginning that he made was the scale - **the whole UNIVERSE is about him,** not just an individual personal bubble of things around him.


  [1]: http://movies.stackexchange.com/a/828/235