[edw519]

Ego.

"Not getting along" is what happens when one believes that "I" is more important than "we".

Once one gets beyond themselves, one can "get along". They still may not agree, but now they've put themselves in a position to solve problems, not perpetuate conflict.

This is also true in the general class "Why x can't get along with y," not just for programmers and business type people.