0. The Fool :

Powerful and fresh, the Fool card traditionally means a new beginning. Starting off the beginning of the tarot deck with Number 0, the card shows the infinite possibilities within having a fresh start. The yellow background of the traditional Rider Waite card helps symbolize the optimism that is to come as yellow presents the psychological behavior of Optimism. 

The imagery displays a dog nagging at the foot of the Fool but the Fool pays no attention to it. This helps represent the negativity in which is being ignored in order to a fresh beginning to commence. Further into the imagery the cliff that the Fool is about to jump over has no definite ledge on the other side so having Faith in the progress of the new beginning is key for those who see this card. 

Hence the meaning of the being “A Leap of Faith” helps reassure that one is not being a fool per se by taking such a leap because it take faith to indulge in the new beginning. Not knowing where that leap may take you takes a lot of optimism in the future but is still worth it as long as you keep your eyes on the Sun, aka the optimism of life.