Gah. I know the feeling. My 2013 Cooper S goes up for sale this week. You’ll join an august club of fathers and family men who have sold cars and motorcycles. In my own family this has consisted of a 1962 Vespa Allstate, a 1972 Chevy C-10 (402), 1966 Chevelle SS (396), 1970 Kawasaki kz1000, and the real killer . . . a…