I made the transition after 12 years as a developer. One of the issues I had was mistakenly assuming all the people working with me would be easy to get along

I made the transition after 12 years as a developer. One of the issues I had was mistakenly assuming all the people working with me would be easy to get along with and hard working, which was how I behaved and is a factor in my becoming a manager. It's not that way at all. You see the 80/20 rule play out, where you have a few A+ players who do most everything, a few people who do decent work, and then a handful of duds. Attitude-wise, the harder people work, the more pleasant they tend to be. The duds can be indifferent towards you or even hostile. Being a developer and being used to controlling my work product, I had to make a shift to trusting other people blindly and that wasn't easy for me. Over time, I realized it was the most effective way to get people to do their best work though - trust that they'll give good results until they repeatedly prove otherwise.