This is a list of 13 things i would talk about starting from most likely to least likely to talk about.
1. Gossip
2. Intimate Details
3.Lifestyle Changes
4.Hangovers and Wild Weekends
5. Negative views on colleagues
6.Work Complaints
7.Politics or Religion
8.Personal problems and relationships
9.Off Color and racially charged comments
10.Blogs or Social  Networking profile
11.Cost of purchases
12.Medical History
13.Salary Information