In 'A Midsummer Night's Dream,' how (in what ways) does Shakespeare convey the theme of love?

Shakespeare portrays love as mad, magical, and difficult. Theseus and Hippolyta are engaged, Oberon and Titania are married, and Lysander and Hermia wish to elope. Meanwhile, Demetrius pursues Hermia, and Helena, his former girlfriend, pines for him. The lovers are mad in the sense that they are irrational, particularly Helena and Demetrius. Helena observes that she is as worthy of Hermia, as beautiful and virtuous, and concludes, “Love looks not with the eyes, but with the mind; / And therefore is wing'd Cupid painted blind.”
The magical element arises when a spell is introduced. Oberon and Puck infect Titania, Lysander, and Demetrius with a love potion. Titania falls for Bottom, whose head has been transformed into a donkey’s. This makes no difference to her, demonstrating that love, whether enchanted or not, is like a sudden spell. Lysander abandons Hermia for Helena, even rationalizing his preference, and Demetrius attempts to fight Lysander for Helena.
Almost every couple in the play experiences the difficult aspects of romance. As Lysander says, “The course of true love never did run smooth.” Theseus and Hippolyta warred before marrying, Oberon and Titania quarrel over the adoption of a child, and Egeus, Hermia’s father, opposes her marriage to Lysander. Both Demetrius and Helena are unrequited in their love, and even the ridiculous Pyramus and Thisby features lovers who are cruelly parted by a wall. In A Midsummer Night’s Dream, love is wild and ridiculous, but, in the end, it all works out.
http://shakespeare.mit.edu/midsummer/full.html