When I sit down to watch a repeat of My Family, I know I’m in for half an hour of laughter. Sometimes the tears running down my face sort, it’s so funny, like the episode where Susan Harper gets her OBE - think broken heel, torn jacket and chocolate fountain. So why do I find that comedy so funny whilst others, like ‘Warren’, BBC’s new sit com, leave me completely unmoved? There are similarities with the main character. Warren and Ben Harper are both miserable old gits