This is one of my favorite movies, it's not that funny, and I'm not really much of a Bill Murray fan, even considering there's a faint chance, very faint, that he might be related, but the movie makes you think.
The first and most obvious thing is how fantastic it would be to start over and know what you know now. Granted, doing the same day over and over seems to be taking it to a ridiculous extreme.
Coming to the main point, it takes him how many times of doing it over to finally get it right? How many to figure out what he wanted? Was what he wanted, love or Andie McDowell, really worth it?
More important by far, over all those days he finally, somehow, learned to be a decent person. How many lives must the average person live through to accomplish the same small thing?
There's more to learn, much more, but for that watch the movie if you haven't. I've hopefully made you want to look under the surface.