
In my nearly 20 years of work experience in high-tech sales and marketing I have only once worked for a very large company, and that not for too long. So I am probably not someone who knows BIG companies (I'm talking here about the ones with 10ks of employees or even more) inside out.
But I have sold to large companies, while working for smaller ones, many times so I have seen a lot of them in action and - often, of course - in inaction!
First of all, I think that once a company reaches a size of about 1,000 employees it should be split into smaller units that are self-sufficient. I doubt that any larger size of organization can be effectively managed by people anymore. It is simply not possible.
So what is it that disturbs me about large corporations and makes them inefficient? To me one of the most important ingredients for the success of a company is that its employees are highly motivated. Best is if they are self-motivated, second best if good managers are capable of motivating them. If high motivation is there, then literally all other things become a second priority as that is the one thing that lets you overcome all challenges.
I have seen many large organizations that showed one or more of the following behaviors:
PoliticsDue to the size of the organization, no-one can oversee what is really going on in every detail. So the best "performers" are the ones that can set up their connections behind the scene and play politics the best. It becomes less relevant how people perform than how well they are able to play politics. Needless to say, this harms an organization.
Reporting OverheadI have seen group managers in large organizations who had - due to the reporting that was necessary to their higher peers - spend nearly half of their time just doing all kinds of paper shuffling day in and day out, filling out an endless number of administration tools all the time so that their actual work was cut by half or even more.
Lack of ResponsibilityOnce you don't see the overall picture anymore but are busy making sure that whatever you do does not overlap with the responsibilities of another person or group in the organization, so you don't care anymore whether your work results change the bottom line at all. Simply because you cannot see and understand how your work actually contributes to the success of the company. This leads inevitably to a culture where, even if someone either internal or from the outside sees how to make improvements, organizational needs are followed first and served rather than pushing improvements through. Often also because, if one tries to do that, he/she will be called back pretty soon and not to step on other people's responsibilities.
Process Oriented ThinkingNaturally, to make BIG companies work, their suborganization follows well set up processes, and each employee needs to follow them. Management of the company spends their entire time streamlining these processes and monitoring that they are executed. Chaos is seen as something that kills a large organization - but why, actually? I think the fear in BIG company management of possible chaos is that they cannot steer things anymore how they like it.
They prefer to protect that orderly house than letting new ideas come up to the surface constantly and challenge the status quo - and possibly their own position as well. Quite frankly, I think that chaos is good to a certain extent, and can actually let a company move faster, as long as there are possibilities for everyone to bring up ideas and everybody can push - if it makes sense - through the organization.
Lack of Decision MakingI have seen many large organizations needing years to get anything done, even where the advantages in terms of cost savings, efficiency improvements or even helping with winning more business are obvious. An army of people are involved but no-one is taking it to a level where a final decision can be made. Everyone just confirms that it is actually good but then, rather than actually making a decision, simply pushes it to another group, giving them the job of deciding what to do. Endless rounds of meetings that cost a lot of money are wasted on reports that are only read by a few people - and even fewer people act on them. "I looked at it and I think that it is good but now the other group should take a look too and then decide what to do with it" is the common "job done" attitude. In my opinion, it would often be much better not to waste time but push it to some other group right away. Real supporters and champions are rare in large organizations. This is BTW also true for top management that I have seen. There things go in the other direction. Instead of making an obvious decision quickly, things are pushed to expert departments that are not too happy to get work now from top management but, OK, will do something with it as it is coming from the top, so have to tell them something.

The above are just a few of my observations, and led to frustrations when I had to cope with large corporations as possible clients. If you still need to make your living cutting through all this crap, then certain attitudes are needed, but mostly one thing over all: patience and persistence.
There is a nice book out there that I can recommend to all who are in similar situations:
Bag the Elephant, along with its successor,
Be the Elephant (great book titles, too). Steve Kaplan sees such companies as friendly elephants that need to be treated properly and their needs looked after if you are to be able to win them as clients. So not as negative as I see it, but simply practical. Not trying to change what cannot be changed anyway but adapt appropriately. That's easy to accept for me as long as I don't have to become an elephant myself.