I have been working in banks as a business analyst for the last 2 years and 8 months. These are some of the things I have learned.
A chain is really only as as strong as its weakest link. The obvious way to control a large group of people is by organising them into hierarchical supervisor-subordinate relationships. Supervisors can then control subordinates by sending and receiving information through these hierarchies. There is an inherent weakness however: the flow of information typically passes from one person to another, forming a long chain of communication, and all it takes for the entire chain to fail is one person not relaying information effectively. This creates a plethora of other problems. For example, it creates a situation where you might have a lot of responsibility but very little mandate to act on that responsibility, since everything you do has to be vetted by hundreds of people above you. By the time they approve it, chances are that it might not be necessary anymore.
Things are never as simple as they seem. And we have a tendency to oversimplify things. This is bad. Things are never as simple as they seem. When you think something is going to take you X hours to complete, multiply it by π (3.14159) to get a better reflection of how long it will actually take (thanks to my brother for this one).
Always be pragmatic about stuff. I care deeply about my craft. I know you care deeply about your craft. People who care deeply about their craft tend to be perfectionists. Sometimes this is good, because it means that you will deliver a quality product. But more often than not, people don’t care about perfection, people care about delivery, and for you to be able to deliver you will have to be pragmatic (that is, you’ll have to make some compromises on quality in order to deliver).
Focus where the pain is. This is arguably the most important learning. This puts everything else into perspective. It determines how successful you feel. Don’t just do stuff for the sake of doing them. In fact, don’t do anything if it’s not directly addressing some real pain somewhere. Add value.