Satan against the World
This topic is one that I think about a lot, I think Satan does bad things for the wrong reasons, but don't we all?
I'm not saying that he is the best person in the world, I think he's just human.
For example:
Let's say your friends started a roomer about you, that would probably make you feel angry, and a lot of the time you would want to get revenge on them. Now I'm not saying that's okay, I am simply saying you're human, whether you're the president or you're the guy that lives in his mom's basement. YOU MAKE MISTAKES! And that's fine.
Back to the actual topic, Satan was proud, he wanted everybody to worship him. The bible says that his wings glowed less and that he felt ashamed. So then, he went to the lesser angles and tried to pursue them to join him in a better place. When God found out about this he threw him out of Heaven.
Now I'm guessing he was feeling like you when you're angry and want to get revenge on the person who hurt you, that person, in this situation would be God. But since God was too powerful for the Devil to take on he decided to take on us and prove God wrong.
What I mean by that is that Satan wants us to join him, to make him our king, so I guess he thinks that by hurting us (taking us on) he will change our minds about worshiping Jesus and follow him instead. (proving to God that he would not reign the nations)
My conclusion is that when God threw Satan he took back the angel quality he previously had and left him human. Then Satan wanted to get back at God, but he also wanted to be great again, torn between the two decisions he left and to this day is trying to climb back up to power.
(Still, it does not mean it is okay to torment us!)