In Sylvia Plath's "Mirror," what does the mirror meditate on most of the time? Why is this significant?

""
byis a two-stanza poem in which a mirrors perspective on its existence and interactions with
humans is offered in the first person.

The sixth line of the first stanza is
Most of the time I meditate on the opposite wall.

We can deduce that the
mirror reflects the opposite wall. The wall...