Why does it seem in the bible that god is a selfish and vengeful being?

if one paying very close attention to the events described throughout the bible it seems like God is nto so much a loving and giving God but is actually a vengeful and overbearing God who will not hesitate to bring catstrophe to anyone who deviates from what he wants from them. He does not seem to have any patience at all or be able to see things from more than one perspective. He was very destructive throughout the bible. he did such things as flood the entire earth allowing only a handful of humans remain alive (only the ones willing to do exactly as he ordered them to do). He brought great pain and discomfort to entire nations many times. He turned a woman into a pillar of salt just for looking behind her at her home she was walking away from forever..He put the devil here to tempt us repeatedly 24/7 and then when we give in to temptation he punishes us for it. how can he be called a loving god when he does all of these things. He is not so much unlike some of the most mean people who have ever lived. His actions match closely to those of Hitler or Sadaam Hussien, or Stalin when he wiped out entire nations of humans for not doing his desires Only complete devotion was and is acceptable. Why give man a brain to think with if we are not supposed to have the option of enjoying our own beliefs without having to fear punishment for doing so. Hwe is vengeful in the fact that if he is such a powerful entitiy he could easily stop man from doing things he does no want man to do but insteed he allows these things to be done and then strikes out against the ones who do them. A loving god would have prevented these things from happening thus not creating a need to punish later. there are far more acts of retalliation against mankind in the bible than there are of rewarding man for doing the thing he wants us to do. And what is said to be the ultimate reward cannot even be proved to exist because to reiceive it man must die which is also vengeful in its own way.