Naming your two cats (who are brothers from the same litter and look almost identical) 'Purrington A. Purrington' and 'Purrington B. Purrington,' is that it becomes almost impossible to determine 'Which One is A' and 'Which One is B.'
Although, the same problem would arisen if I had named them, say, Frank and Dave. Or Tom and Jerry. Or 'The One Who Likes to His Stomach Rubbed Constantly' and 'The One Who Wants to be Chased Around the House Constantly.'
Ultimately, the real question in life is ... "Who's on First?"
Don't you agree?