Analysis of U and I

All the letters of the alphabet
   The righteous way should choose,
But two of them, especially,
   Should mind their P's and Q's;
A deal of trouble in this world,
   And much that goes awry,
Could be prevented easily
   By these two, U and I.

If U and I are cross, you see
   There's bound to be a fuss;
If U and I untidy are,
   Somewhere there'll be a muss.
If U and I are selfish, there
   Will some one suffer wrong;
If U and I rob birds' nests, why,
   The world will lose a song.

If some one feels dejected, or
   'Tis cloudy for a while,
The sunshine may come back again
   If U or I but smile.
If U should grumble, whine, or pout,
   Or I should snarl and fret,
A storm would soon be raging that
   We should not soon forget!

So U, look out, and mind your ways!
   As I must likewise do,
And keep a cheery corner where
   The skies are always blue.
The A's and B's and E's and O's
   Do work that's good and great,
But U and I can do the most
   To keep this old world straight.