A

a is also for agatha, apple, alice, apache, again, augment, antelope, awesome, australia, antarctica, astronomy, alligator, association, antipathy, anger, addled, aggregation, assonance, alimentary, antiquated, annoyed, allaphone, aphrodisiac, alumni, almighty, afraid, afford, afro, animosity, allegiance, android, androgeny, arithmetic, amorous, adored, aproached, allibrandi, ameoba, accustom, antedote, anticipate, appear, aubergine, accidental, affluent, agog, adhere, accordian, ad infinitum

A ship captain is a good man to marry if it is a marriage of love, for absences are a good influence in love, and keep it bright and delicate; but he is just the worst man if the feeling is more pedestrian, as habit is too frequently torn open and the solder has never time to set.

Robert Louis Stevenson, Virginibus Puerisque

A knowledge that another has felt as we have felt, and seen things, even as they are little things, not much otherwise than we have seen them, will continue to the end to be one of life's choicest pleasures.

Robert Louis Stevenson, Roads

a is also for agatha, apple, alice, apache, again, augment, antelope, awesome, australia, antarctica, astronomy, alligator, association, antipathy, anger, addled, aggregation, assonance, alimentary, antiquated, annoyed, allaphone, aphrodisiac, alumni, almighty, afraid, afford, afro, animosity, allegiance, android, androgeny, arithmetic, amorous, adored, aproached, allibrandi, ameoba, accustom, antedote, anticipate, appear, aubergine, accidental, affluent, agog, adhere, accordian, ad infinitum

i find a very useful when referring to the nonspecific, but when you have a particular to mention, there's nothing like the.

i think A is a very cool letter, since a is the first letter of my name a for anne! that is me! the letter a!!!

A is for Kid A by Radioheads
Kid A is also what my true love calls me.
Hey Kid A
He also calls me A for Angel.
Hey A Kid A.