On Rosh HaShana and Yom Kippur, people should be very careful to avoid socializing in shul. Normally, more people are found in shuls during these days and it is likely to see people that one has not seen in a while. People should be very careful, though, to remember the seriousness of these days and to act with the proper awe while they are in shul. This is especially true for conversations between men and women, which can happen during breaks.