What is a frenemy?
“A frenemy is a person you spend time with, enjoy talking with, and rely on at work—but you can't completely trust. He or she is so much a part of your working day that a relationship that isn't strictly business between you two is not just assumed—it's unavoidable. And, day in and day out, it's not unpleasant.
But at the same time you have been burned by this person, who hasn't demonstrated the unyielding loyalty and support you'd expect—and get—from an out-and-out friend.”
What drives (or motivates) a frenemy?