Anyatha patityasnkya (13)
Otherwise one may fall. Rituals and practices should be practiced for three reasons.
The purpose of the rituals is Peace, Purity and Love. If the rituals and prayers are not performed, there is every possibility of falling from the peaceful mental state. There is every possibility of falling from the purity and calmness.
One may ask, "what is wrong in living without rituals and worships, if I lead a harmless life?" In worships and rituals we develop an attitude to offer everything to the Divine, by which Sattvic attitude is developed. In the worship-less life, there is every possibility of the interference of material ego that leads to Rajas and Tamas. Anger, jealousy, pride, tension, complexes and lust may occur easily in the worship-less life that further leads to physical diseases.
One may not understand the significance of worship when one is leading a happy life. But happiness in material life is not permanent. As soon as one finds oneself in a agony, stress and misery, one realizes the significance of worship.
That's why Kabir says:
Dukha me sumirana kare sukha me kare na koyi,
Jo sukha me sumirana kare dudukha ko na hoyi.
"People worship in misery and not in joy; where is misery to those who worship even in joy?". It does not mean that tragic events do not occur in the worshipper's life.