Ah, the innocence of the engineer on the cusp of a new management position.

This is more or less what every engineer thinks when they start a "bridge position". Very few survive, because the reality is that the management world is much different than the world we engineers are used to, even after we have a lot of experience as an employed engineer. We think that since we've seen a lot of bosses come and go and met and talked to a lot of them, we know what works and what doesn't, etc. It's not like that. Management plays by a whole different rule book.

When it comes down to it, management is primarily a psychological position. Soft things matter much more than hard, measurable things. Engineers live in a meritocracy, even if they think their employer is bad about that. The numbers and/or code work and have merit, or they don't. Someone is right and someone is wrong.

Management is the opposite extreme. Your job is to keep your reports happy so that they do the job the company wants to do them as well as possible. Yes, some of that involves acquiring resources and removing barriers to implementation (the part we engineers naturally think of, and have a lot of ideas about how to improve), but most of it involves making sure that everyone likes you as far as is possible, and that in cases where something that makes someone unhappy must be done, the lowest-value person is affected in the least direct way, such that they don't stay off your side for very long. When you are a manager, you are really a full-time politician. To be successful, you must always be campaigning, not on issues that matter or on the most correct or meritorious position, but on whatever will make you most liked, as broadly as possible.

When this was me, I didn't anticipate the heaviness of the political aspect. I thought as long as I was more or less right and proved myself, it would be fine. I thought that if I fought for righteous causes, the truth would bare out and we'd all win. What I had to accept is that this is not how the real world works. I was forced out before my first project even had a chance to wrap. I don't think I was overtly rude to anyone; the issue is that when you're a boss, people nitpick and look for things to be offended about. You have to actively counteract that. If you do something adverse to someone, even something you think is miniscule, you must do it in the most gentle way possible and really think about it. If you don't do anything bad but aren't as nice as some of the other bosses, that will come back to bite you too.

I made a powerful enemy just by politely taking a rain check on a lunch invitation. I thought that was fine and not a big deal, because everyone knew we're all really busy and that having lunch is not a major priority for most people. Turns out, it's not fine.

I made several not-powerful enemies because I didn't regularly pay for everyone's lunch or bring in donuts, cookies, or some other type of treat, which a couple of the other guys did. It doesn't matter that nothing in my job description involved procuring donuts or lunch for everyone. It doesn't matter that I was very generous in other ways. It doesn't matter that I would rather spend that half-hour that I would've spent waiting in line at the donut shop on actual work, like writing a few extra tests or even sitting in a pointless management-level meeting where nothing got decided. All that mattered was that some other guys did this thing, and I didn't. I was expecting people to note these other things and care, but they didn't care because they didn't benefit directly and personally. I wasn't running a tight campaign. A tight campaign wouldn't have let any other employee at any level be more popular or more important.

The problem, of course, was that I didn't go into it to be a politician; I went into it to build awesome stuff and have authority to see it done the right way. Once you're a manager, the only thing that you should care about building anymore is your personal reputation within the ranks. (I've found this to also be true if you want any room to negotiate as a non-management employee.) Doesn't matter if it's better for the company long-term. That's not going to help you. All it means is that they'll still be around to fire you. What matters is that you're exploiting your position to groom your personality cult. Nothing else will help you, because most people do not understand anything else.

One could argue that these are exceptional situations, but I don't really think they are. Maybe someone else would find some other minor thing to nitpick, but they'd still do it. Everything you do reflects back on you, and it's not about merit or correctness anymore. It's about feelings -- feelings that are completely and utterly unreasonable, as feelings often are. When you become a manager, you are the steward of feelings. It becomes your job to ensure everyone on your team is all good feelings and, furthermore, that everyone else in the whole company is all good feelings too, and it gets very personal. Most people cannot make a decision based on the merit of something, they can only make decisions based on appearances.

After trying my hand at this for a while, I decided that I'd much rather stick to coding. Managers become managers because they don't know what else to do with themselves. They are forced to live in the ghetto dictated by irrational, unpredictable human emotion that engineers usually consider something that was left in junior high. Once you get into pretty much any other field, any field where empirical thought processes are not a fundamental component of the day-to-day workload, you realize that ghetto never really got left behind by any of your non-technical peers; it's the only world they know how to live in.

Good luck man.