I learned how important a boss is to job satisfaction when I was an intern at the USDA-NRCS in college. My first summer I had a great boss. He was genuinely interested in my professional development, and made it a point to include me in relevant projects, training, and meetings. He also did not hesitate to give me real work to do, and listened to my questions and ideas for improvement. He created an open and friendly atmosphere by being a good listener, being very knowledgeable (but willing to not only admit he didn't know something, but work to find out), and never making me feel like I was stupid. I could go on and on....
The next summer, he had been promoted, and there was a new boss. I didn't meet him for a week, because he was always out doing "projects" but no one on the staff know where he was or what projects he was working on. When he was finally in the office, he waited to have a face to face meeting with me, and the whole time he was obviously distracted and wanting to do be doing something else (picking up the phone when it rings, not turning his cell sound off, looking at his emails, etc). He told the whole staff that he did not want me working on any projects on my own and didn't give me anything to do in the meantime. So, I just went out in the field with everyone as often as possible (where I wasn't allowed to do anything, but the staff usually would let me anyway because I had worked with them the previous summer). Eventually, he told his supervisor (who had heard glowing reviews from my previous boss) that I was not doing a good job in front of a member of our staff (who stuck up for me). and that led to me being transferred to another office for the rest of the summer. After that summer, I decided not to stay with the NRCS after graduation. (also, that second boss was demoted).
Long story short, new bosses, be like my first NRCS boss.