history: It's always sad to see someone you liked from work find a different job. It's always sad for me to see a friend from work_comma_ leave and get a new job. Yeah that is pretty tough. Especially when you really like to work together.
current: Yeah! It's one of the main reasons for liking a job, is the people you work with and become friends with.
next: Then you have to meet their replacement and try to get to know them better. It usually isn't the same.