Work is fun for every father if you have a loving family waiting for you and working for. If the purpose of your work is of loving nature, then work is productive fun and no "work" in conventional meaning.
A father who feels true love from his family works as long as needed until "job done", no matter ho whard the work and how many hours per day.
True love is the key to a happy family. A happy family depends on a hard working husband and father. The love from his family is the driving force behind strong families. The man always should be the stronghold of family and society. To do so however a father needs to see a reason to work for. Without a worthy goal there can be no powerful motivation. Love is the strongest reason and most powerful motivation to work hard and honest all life long. All eternity long. The sweetness of love from his family - children and wife - is the power needed to succeed in hardest work.