I just finished reading a biography of Steve Jobs, the charismatic co-founder of Apple Computers. He is able to attract top talent to any company he starts, and those computer engineers willingly work 90 hour weeks on his behalf. Yet, after he charms and attracts them with his vision of the future (often referred to as his "reality distortion field"), he is often abusive to those same employees, paying them poorly, taking credit for their work, and shunning them (even after many years of service) if they are critical or disloyal in any way.
So why do people continue working for Steve Jobs? I'm reminded of the psychological concept of "partial reinforcement", often used to explain compulsive gambling. It goes like this: Slot machines reward their players at random intervals. You never know when you will be rewarded, so you keep playing. Random reinforcement turns out to be one of the most powerful human motivations. Some people forget to eat or sleep, regardless of their finances, in pursuit of possible reward.
Followers want to identify with their leader's emotions. They want to please him, and receive approbation and approval in return. They are happy when he is happy, and sad when he is sad. That is the nature of being a follower. If the leader is abusive toward them, they feel stress and dismay, but also more motivated to please him in the future.
Steve Jobs naturally taps into the motivational power of partial reinforcement. He is just being himself, although he is more rare breed than the rest, the distribution of traits at work.