There is a popular Saint Therese prayer card in which people ask her for a favor, and then promise to help more people learn about her life. This is a good thing, because becoming more familiar with this remarkable woman can help us look at God in a new way.
Saint Therese viewed God as a merciful friend whom she could always turn to in time of need. He would always be there for her, and He would always pick her up, even if she had fallen. She had a very simple, childlike faith, in stark contrast to a heresy known as Jansenism, which had swept through her native France, and still hadn't completely gone away.
Jansenism takes a very rigorous approach to God, and views Him as a distant, cold and punishing Creator, instead of as a loving and forgiving Father. This heresy also makes it more difficult to get close to God, because we begin to fear Him. It also makes it harder to love God, because why would we want to love such a harsh Deity.
Anyway, Saint Therese seemed to be God's antidote to this heresy, because she had such total trust in His goodness and mercy.
This is part of the reason so many Catholics around the world have adopted Saint Therese as a patron, because her spirituality is so simple, yet so profound.