Whereas “It’s a Wonderful Life” tries to answer the question “What if you were never born?” “Groundhog’s Day” tries to answer the question “What if tomorrow never came?”
In “Groundhog’s Day,” we see the protagonist Phil Connor living the same day over and over again. At first we see the self distructiveness where gluttony, breaking the law, and even suicide pay a role in the days. Phil has the worst day of his life during the first few reoccuring days. This is summarized by his weather report:

It’s gonna be cold, it’s gonna be grey, and it’s gonna last you for the rest of your life.

Eventually however Phil sees his unique situation and uses it to his advantage. He has the best day of his life – saving a man from choking; helping change a tire for old ladies in distress; and eventually getting the girl in the end. This “best day ever” permits Phil to experience tomorrow – something he describes as “different.”
Success is not measured by how much money we have; how many friends we have; how big of a house we live in. It’s what we do with our time here on earth. For George Bailey, it was important to know how much of a difference he had made in his life. For Phil Connors it was living the best 24 hours so that he could see tomorrow.