In Shakespeare's A Midsummer Night's Dream, what are three differences between the city of Athens and the magical forest?

One difference is that the city is a place of order, while the forest is a place of disorder. In Athens, Hermia must marry the man her father chooses, die, or become a nun. She flees these laws by running into the woods with her lover Lysander, where they cannot be found and where these laws do not apply.

The wood is also a site of magic, where the fairies dwell. It is there that Puck and King Oberon apply a love potion to the eyes of two mortal lovers and Titania, the fairy queen. It is in the forest where Puck transforms the actor Bottom’s head into an ass’s and Titania falls in love with him. The enchantments of the woods feel like a dream to Bottom and the lovers. Bottom wishes to make a ballad of his experiences called “Bottom’s Dream,” and, when the lovers awaken, Demetrius is confused: “Are you sure / That we are awake? It seems to me / That yet we sleep, we dream.” The wood represents magic and illusion, while the city is reality.

One obvious difference between Athens and the surrounding area is that the city is within the realm of human civilization, while the forest is under the control of nature itself and the fairies, who help control the environment. Titania says the quarreling between her and her husband is disrupting the earth’s cycles:

… the spring, the summer,
The childing autumn, angry winter, change
Their wonted liveries, and the mazed world,
By their increase, now knows not which is which:

The humans have little control over what happens to them in the woods. They become lost and are ruled by the laws of magic and nature. In the end, there may be some balance between the freedom of the forest (Hermes is allowed to marry Lysander, and the fairies bless the couples) and the reason of civilization (the spells are--mostly--lifted).