The hardest part of any corporation is that of philosophy towards members. While we cannot deny that corporations are built on the backs and fortunes of their members, the corporation itself also becomes an entity that must be taken care of and nourished if it is to thrive. Thus a true dichotomy is established, but the most difficult part about this dichotomy is that there must be a true balance in order for it to work properly.
From a psychology perspective, members of a corporation tend to care most about themselves and improving their own standing or their own wallet. Every player has a dream or a goal they want to accomplish in the game, whether it's flying a Dreadnought, mining enough ore to make even the most seasoned industrialist sick with envy, or producing and selling enough items to fund the purchase of PLEX cards that effectively make the character self-sufficient. It's the same analog as real life - most people care about their own well-being and their own accomplishments, whether it's driving the newest car, making lots of money, or owning a brand new beautiful home. (There are people who are teamwork-oriented but we'll cover those later)
As I stated, the corporation itself is it's own creature. The players make it possible and make it happen, but the corporation requires the cooperation of it's players to stay alive. When a corporation truly comes to life it can be a magnificent thing, but it takes a good CEO to keep the corporation stable. As long as the corporation stays stable the members within the corporation are able to do what they want. But members don't always want to do the same things, which means that a good CEO must be adept at balancing and motivating. The more balance and motivation members have to help the corporation the more both corporation and member thrives. This is very difficult, especially given that the corporation is made up of people who have their own goals and dreams and desires.
There are some team-oriented players out there, though these are quite a rare breed. The true mark of teamwork that separates these players is a selfless desire to see the corporation thrive and do well, even at their own expense. Many of these players become or are CEOs themselves, and funnel millions upon millions of isk into the corporation to help it develop, grow, and thrive. Within the ranks of the corporation, these players can often make a good corporation great through taking on duties and responsibilities that others do not want, undertaking greater duties to support the corporation, and doing the odd jobs that the corporation needs to take it to the next level.