Why do so many people go on power-intelligence trips, and turn evil and want to control everything?

I agree with you completely. I do think people are insecure and lack confidence. I think people like to be authority figures at times when they are not, only to make themselves feel better. A lot of people must make themselves appear better than another only to make themselves feel superior to another. Perhaps it's part of human nature. There are a lot of people like this however I know there are a lot of genuine people as well.