Indeed, this night is different from all other nights.  On this night, we celebrate the triumph of freedom over slavery.

Why do we eat only matzah?  To remember the importance of acting when opportunities for action arise.  The Israelites had to flee in such haste that they had no time for their dough to rise or to bake it.  Instead, the sun baked it on their backs into a flat, unleavened bread.

Why do we eat bitter herbs?  To remember those whose lives have been made bitter by slavery and persecution.

Why do we dip the herbs twice?  Dipping the parsley in saltwater reminds of springtime, as the earth comes back to life.  We dip the bitter horseradish root into sweet maror as a sign of hope:  people can withstand the bitterness of slavery only by maintaining the hope of freedom.

Why do we recline? Because reclining at the table is a symbol of freedom

haggadah Section: -- Four Questions
Source: Schachter Family Haggadah