Looking At the Macro Perspective
From personal experience, it seems to me that I look at the big picture far too much. This isn't necessarily a bad thing, but it does create rather awkward situations in a debate. When you're arguing with someone, and he's looking at some small detail while you have the whole thing in view, even if both of you really agree on something, odds are both of you will end up disagreeing.
A lot of my disagreements with intelligent people actually stem from different viewpoints. Usually, I have found that because they look at things from a microperspective, they end up with an opinion quite different from mine, even though we are looking at the same data and facts.
Why? Because looking at the big picture, and placing those same facts into the context of this picture, you tend to get a different view on things. What holds true for the short run might not be true for the long run, or vice-versa.
Other times, people might look at the big picture, but look at it through tinted glasses. One common mistake is to follow the economic assumption of ceteris paribus, i.e. that all variables except those you are studying remain unchanged.
Another mistake might be to avoid looking at the interplay between the variables being studied. If you change X and the result is Y, you have to see what the impact of Y might be as well.
The effect of these mistakes is that people end up with a very linear and overly simplified view of the big picture. Things in real life are rarely as simple as just cause and effect. The effect might in turn cause something else. And if the cause involves altering other variables, then these variables could have an impact on the desired effect.
It is crucial to look at the big picture, and to look at it properly. What seems important at the micro level may really be unimportant at the macro level. At the same time, when plotting the big picture, it is imperative that we not lose sight of all the things we have changed.
Evolving on the African plain, life was very simple for our hunter-gatherer ancestors. Things were simple: if you ran from the predator, you didn't get eaten. If you ran after the prey, your stomach became full. But in the modern world, and in modern society, things are not so simple anymore.
Our brains aren't equipped to think in terms of systems and in terms of the big picture. (That's actually a reason communism failed. The communists thought everyone would understand the big picture and not work against the system, but that's not what happened in reality.) We have to train ourselves to view things from a broad perspective, and to account for all effects of the things we change.