Why do bad things happen to good people?

The Bahá'í Faith offers a number of responses to this question. These include that suffering produces personal growth; that suffering need not prevent happiness, for one can be joyous in the midst of severity; that some people bring suffering upon themselves through their neglecting to follow the teachings of the Prophets; and finally that the reason for some suffering might only be known to God.

Tests and trials make us stronger.

Not until man is tried doth the pure gold distinctly separate from the dross. Torment is the fire of test wherein the pure gold shineth resplendently and the impurity is burned and blackened. At present thou art, praise be to God, firm and steadfast in tests and trials and art not shaken by them. - Selections from the Writings of 'Abdu'l-Bahá,

Shoghi Effendi, 'Abdu'l-Bahá's appointed successor and Guardian of the Bahá'í Faith, wrote:

... As long as there will be life on earth, there will be also suffering, in various forms and degrees. But suffering, although an inescapable reality, can nevertheless be utilised as a means for the attainment of happiness. This is the interpretation given to it by all the prophets and saints who, in the midst of severe tests and trials, felt happy and joyous and experienced what is best and holiest in life. Suffering is both a reminder and a guide. It stimulates us better to adapt ourselves to our environmental conditions, and thus leads the way to self improvement. In every suffering one can find a meaning and a wisdom. But it is not always easy to find the secret of that wisdom. It is sometimes only when all our suffering has passed that we become aware of its usefulness. What man considers to be evil turns often to be a cause of infinite blessings.. - Unfolding Destiny, p. 434.

The Guardian also wrote:

...the world is full of suffering. Bahá'u'lláh tells us that the deeper are the furrows it digs into our very being, the greater will be the fruit of our life and the more enhanced our spiritual development. All the Saints that shine in the history of society had to pass through tribulations. Their form was various but their effect has always been the same, namely, the purification of our heart and soul for receiving the light of God. - Lights of Guidance, No. 678, p. 204.