What makes elections dirty?

Question

As I have observed every time we have an election of any kind, either National or local government offices, it's always stained with dirty and dishonest conduct of it.

Why is it so?

Answer 1

Usually from washing off all the mud the candidates are throwing at each other. And much of it splatters onto the voters as well. 

Answer 2

There is just one aim for most politicians , its to gain has much as they can , and keep gaining more no matter what dirty ways they need to go by to achieve it 

Answer 3

The saying power corrupts and absolute power corrupts absolutely is true. Most politicians do not want to leave the post. They try to rig the election or increase term limit. If it is possible they will create a dynasty.