Diwali is lighting:
The lamp of love in one's heart;
The lamp of abundance in one's home;
The lamp of compassion to serve others;
The lamp of Knowledge to dispel darkness

Every lamp that you light is symbolic of a good quality. There are good qualities in every human being. Some have forbearance, some have love, strength, generosity; others have the ability to accept all as one' own, yet others have a scientific temperament that will uplift humanity; and others have the ability to unite people from all religions. A latent talent is a lamp. When latent talents awaken, that is Diwali.
Don't be satisfied with simply lighting one lamp; light a thousand.
Eg. If you are a good sevak, don't be satisfied only with that; light the lamp of wisdom in you. Acquire knowledge. If you are interested in acquiring knowledge, don't limit yourself only to that. Take an interest in the creative arts, in dance, music etc.

Do you know why we do aarti? It is so that light of our life always rotates around the Divine.
Do you know why we burst crackers? We suppress many emotions within ourselves; cravings, aversions, hatred or too much attachment and we reach bursting point. When there are a lot of worries, people say, "I feel my head is going to burst." If there is a lot of sorrow, people say, "My heart is going to burst."

Knowing this experience, the ancient people said that when you see an explosion outside, you feel similar sensations within you as well. Along with the explosion, there is so much light. Similarly by lighting the crackers, when there is an explosion outside, you release the suppressed emotions and become hollow and empty. You become free and are able to celebrate the festival and distribute sweets. The darkness is dispelled, light has come into the house, and joy spreads. This is a festival of joy.