A Midsummer Night's Dream Theme of Foolishness and Folly

A Midsummer Night's Dream is a comedy, so it's going to have its fair share of slapstick humor. It's obviously funny to watch a man with a donkey's head wander around on stage, but it's a different kind of humor than when Egeus gets absurdly mad at his daughter and decides to have her killed.  Really, it all ends up being two sides of the same coin – nothing, not even murder and death, is taken seriously here.  Misunderstanding is as central to the play as any other element of plot.  Finally, as the play is really about love, you can't avoid embarrassing foolishness.  We all know that.

1. As we spend time with the young Athenian lovers, it becomes apparent that their love for each other seems silly and melodramatic.  Is Shakespeare implying that their love is particularly foolish (maybe because they're young), or that foolishness is naturally to be expected of any person in love?
2. The Mechanicals are the target of a lot of Shakespeare's mockery.  Not only do they not know how a play is performed properly (meaning they lack societal finesse), but they don't even seem smart enough to figure out that they are being mocked.  What's the point of the Mechanicals' silliness and bumbling? 
3. Lysander and Demetrius are enchanted for a good portion of the play, but they were at odds even before the magic kicked in. On the other hand, Hermia and Helena fight with each other and neither of them has been enchanted.  What, besides the magic pansy juice, can be used to explain the rash behavior of the youthful Athenians?
4. One of Shakespeare's archetypes is "the fool" character, who can be relied upon for jokes and mischief, but also often provides some sharp personal or philosophical insight.  Is there such a character in A Midsummer Night's Dream?

When Shakespeare makes fun of the Mechanicals, he's making fun of uneducated commoners.

The silliness of the Mechanicals isn't meant to degrade those characters or their social status. In fact, Shakespeare pursues a far more egalitarian course: the folly of the Mechanicals – confused, misled, and misunderstood by each other – matches exactly that of the young Athenian lovers lost in the wood.