Why do a Sagittarius does not get along with a Virgo?

all mutable signs don't mix well if born 1st ten days of their sign-often called the 1st decan Pisces and Gemini are the remaining mutables now if born the 2nd ten days or third you get aditional signs that get along as an example a sagitarius with dob between the 10th and 20th of December would go well with a Virgo whose dob is 10 to 20th of September because in these two sectors Leo and Taurus show up and are congenial In short there are 3 kinds of each sign so in a practical sense 36 The real or decan zodiac is not common in commercial Astrology making it of course about a third accurate