Power: The Formula to Create Mr Hyde

Is it just me, or is there one to many people in places of power that don't know how to use it. It seems to happen quite a bit at work. Granted the people who I currently work with are pretty good at what they do, but it's the people that substitute for them that show their Mr Hyde when they're in charge. These people are fine to talk to and be around, but as soon as they're in charge they meta morph into someone totally different.

Why is it that most times in life those who have power don't know how to use it, and those who do know how don't have it. This happens all the time. Either people get power and become complete idiots, or being an idiot is the base job requirement to move up. I'm definitely not saying that this happens with everyone, but it seems to occur more than I would like it to. Power will do one of two things, it will either show us your greatest failures or show us your greatest potential. Lets hope it's the latter.