Why was the bible god so angry and bitter in the Old Testament?

God created all things from nothing. He made man and woman and put them in a garden for a relationship with Him. They chose to disobey His one command. He put them out of the garden. Adam and Eve had two sons -- one killed the other. All through the Old Testament are stories of people who chose to worship idols, do all kinds of wrong and turn their back on God --wanting to set up idols or themselves to worship. God promised He would send the Solution to the problems. The New Testament shows that Promise has come in the flesh to take care of the sins of mankind --all we have to do is accept Him.