Why do peoples personalities change when they get a promotion at work ?

Ive seen this happen on many occasions in the work environment and it ceases to amaze me how people can change so quickly usually for the worse



Is it just me thats noticed this ?Why do peoples personalities change when they get a promotion at work ?
sometimes a little bit of power goes to peoples heads.Why do peoples personalities change when they get a promotion at work ?
A few reasons I can think of:



1. They're under more pressure.

2. They're trying to live up to what they perceive as management's expectations of them.

3. They're in a new job, and anyone in that situation is trying not to screw up.
its not about the promotion, its about the extra responsibility that the promotion brings, promotion means a higher level, a lot more to do a lot more stress, not the fun loving bit on 'ground level' (do not mean this wrong) here's an example, i was a student nurse for three years, and yes i had responsibility but overall i was not accountable because i was under the guidance of my supervisor, usually a staff nurse. when i qualified as a staff nurse i soon realised the pressure i was under, it was quite frightening not only did i have to teach new students. i was also accountable for health care assistants and the running of the ward. the higher up in your career ladder you go the more responsibility you have so you have to change to cope with it, its not all fun and games then
I have wondered that myself. While I agree with the other two answers, there has got to be something more. I have seen people's personalities change from polite and easygoing to rude, egotistical, territorial and pretty much complete loss of common sense and courtesy - to the people that they perceive as being ';below'; them. My guess is it's always been there waiting for the opportunity to come out. And that you really didn't know these people the way you thought you did.
No, it happens where I work !! Some people really lick a*** when they get a promotion and have to be seen to be 'in-charge' it f***s me off too!!