I do not know why the devil is bad to Christians and Jews, but I am Muslim so I will answer this question according to what my religion says:
A long time ago, when Adam became a prophet, God (Allah) told all his angels to bow down and submit to the will of Adam. All angels did as they were told, except for one individual named Iblis. Allah asked why he had chosen to disobey him. Iblis responded, "I am made of fire, Adam is made of clay. I am better than him. I do not need to submit to him." Allah got really mad. He banished Iblis from heaven for committing such a shameful crime (disobeying God's command). Allah told Iblis that his new name will be Satan (a.k.a. the devil). Iblis's punishment will be that he can wander around the world and live in a low status. He will be hated and forgotten. Iblis's ultimate punishment will be that he shall go to Hell on the Day of Resurrection.
The devil is evil, so if you're full of the devil you are acting in a bad or evil way.
there is no bad with out good so there is no god without a devil. everyone already knows about the bad but now they are trying to see the good side and leave the bad behind.
In the Bible, 666 is the number of the devil.
To not believe in any god or devil is an atheist, whether it is bad or not is your own opinion.
i say no because bad things can come from Yourself, God, and the Devil the devil so it can go either way and just look in Easter through Psalms
In theology, the devil does not act bad, it encourages humans to make bad choices through temptation.
No.
There is only one (devil) so it only happened once.
God told Adam and Eve not to eat from the devil's tree so Eve dared Adam to eat from it so that is why.
his good and bad! His a tazmainian devil and his a pet
Yes
No ! except the devil ............... :)