How may one analyse the Poem "Warning " by Jenny Joseph?

This hilarious poem
which is incredibly popular in Britain is above all an ironic reflection about aging and the way
that when we are old it is permissible for us to act in strange ways and do things that
"normal" people would never ever dream of doing. The label of being "old"
clearly gives us license to be slightly crazy, and, as the poem says, "wear purple"
and other colours that clash with...