 The series originally was to focus on Rob at the office with Sally  Rogers as the lead female character and Laura as a minor one. The  character of Laura became so popular that Mary Tyler Moore (qv)  became the lead female character and more of the focus of the show  shifted to the relationship between Rob and Laura. Many times  situations at the office were still focused on Rob and Laura. This  put a strain on the relationship between Rose Marie (I) (qv) and  Mary Tyler Moore (qv), and while the two ladies got along well,  they never became close friends.