What is an incident that supports the secondary theme, "Oh, what fools these mortals be," in Shakespeare's A Midsummer Night's Dream ?

Puck say this in the play " Lord, what fools these mortals
be!"

Some examples of foolishness are Bottom, who mixes up
his words. He is also made a fool of, when he is given the head of an
ass.

Demetrius shuns the woman who loves him (Hermia) and
chases the woman who does not love him (Hermia).

Hermia
disobeys her father and the Duke even though she knows that the result could lead to her
death / life in a nunnery.

The foolish behaviour of the
lovers is due to Puck and Oberon's interferance (magic eye drops) and not of their own
making.  It is easy for Puck to blame them for the foolishness but he fails to see he is
the cause.

Duke Theseus also implies foolishness/madness
when he compares lovers to madmen.  He says, "lovers, like madmen and poets, are
fantasists, "of imagination all compact " (Act 5, scene 1, 8).