As mentioned before, there are always one or two individuals at any large company, with county departments being no exception, that are more difficult to work with then any one person should be. Sadly you never know if their reasons are due to outside, non-work related reasons (family death and illness are good reasons someone might be more down in their life than others) or they are just burnt out on work and life in general.
If burnt out, they tend to bring everyone around them down. If in management, they tend to be overbearing and difficult to work for / with. While you cannot avoid this type of person with your first position with the county. Remember to always be pleasant, do the work, follow their instructions to the letter and when you have enough time in position to put in for a transfer, do it. Once working at the county, you can talk to the friends you have made (and their friends) to find out what different department and different managers are like, thus avoiding the poor managers completely.
Every large group has one or two of these types of people, so it is better to learn how to work with them and avoid if possible. Just consider it paying your dues and learning about human behavior, whatever you do, don't allow another persons sour disposition to take you down with them. Life is too short for that. Remember while you can not control another, you can control your reaction to the situation...at the end of the day we are all responsible for our own actions. If everyone takes responsibility for themselves things tend to have a way of working out in the long run.