A.E. Housman

When first my way to fair I took  
    Few pence in purse had I, 
And long I used to stand and look  
    At things I could not buy. 
Now times are altered: if I care 
    To buy a thing, I can; 
The pence are here and here's the fair, 
    But where's the lost young man? 
—To think that two and two are four  
    And neither five nor three 
The heart of man has long been sore  
    And long 'tis like to be.