The primary characteristic of an aspiring socialist leader is hubris. They believe that "in theory" socialism is a really great thing (as opposed to the individual crushing system is it) and since they're so much smarter than anyone else who's tried to implement it, they know that THEY'RE the one who will finally get it right.
The secondary characteristic is a combination of unbridled greed and being completely amoral, so you can justify anything, telling oneself that as you're getting rich and the people are living in squalor, you're actually helping them.
Sound like anyone we know? Certainly one who's assumed room temperature recently, but there are far too many others!
Mark